Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

Office of Planning, Environment, & Realty (HEP)
Planning · Environment · Real Estate

HEP Events Guidance Publications Glossary Awards Contacts

United States-Mexico Land Ports of Entry Emissions and Border Wait-Time White Paper and Analysis Template

4.0 Case Studies

This section provides specific examples of how the information presented in Section 3.0 can be applied to evaluate emissions at a specific border crossing, as well as ways to evaluate alternative control strategies or scenarios at the border crossing.

4.1 Characteristics of Border Crossing Used in Case Studies

Ysleta-Zaragoza (Zaragoza) is located in eastern El Paso. It connects to I-10 via State Highway 375 (North Americas Avenue). Southbound passenger vehicles are tolled at $2.50, commercial vehicles at $3.50 per axle, and pedestrians at $0.50. Northbound tolls are 23 pesos for passenger vehicles, 137 pesos for commercial vehicles (5 axles), and 5 pesos for pedestrians. A northbound dedicated commuter lane (DCL) booth is available at Zaragoza. Drivers pay 24 pesos per DCL crossing in addition to CBP's 5-year SENTRI enrollment fee. The bridge currently is open 24 hours per day for private vehicles and from 6 a.m. to midnight (Monday-Friday) for commercial vehicles.

Two case studies are presented:

To simplify the presentation the case studies focus on daily average conditions for summer in 2010. Two pollutants are considered, oxides of nitrogen (NOx) and fine particulate matter (PM2.5). Both strategies being analyzed consider northbound traffic only. In the following section, composite emission rates common to both case studies are developed. Subsequent sections then apply those rates to estimate emission inventories for a no-action alternative and for each case study strategy.

4.2 Development of Composite Emission Rates

Composite emission rates for PM2.5 are developed within this example, and corresponding calculations are available separately for NOx. Subsequent portions of the case study then apply both sets of composite emission rates to quantify PM2.5 and NOx emissions. The starting point for developing composite emission factors are the MOVES emission rates estimated for the El Paso port of entry as part of this study (provided with the supplementary electronic data accompanying this report). Three weighted averages are applied:

Weighted averages are applied in two steps to develop the composite emission factors. First, the time-of-day factors and gasoline/diesel fractions are applied; then the vehicle class weighting factors are applied to the results to produce composite PM2.5 and NOx emission rates for uncongested movements, creeping queues, stop-and-go queues, idle, and vehicle starts. The calculations are walked through separately for each process below.

Case-Specific Running Exhaust Composite Emission Factors

Time-of-day factors and gasoline/diesel fractions are applied to running exhaust emission rates in three tables:

Only composite PM2.5 emission rates are provided here. NOx emission rates were generated via a similar process; tables are available separately).

There are five sections in each of these tables. The first four sections correspond to the four periods of the day (i.e., 6-9 a.m., 9 a.m.-4 p.m., 4-7 p.m., and 7 p.m.-6 a.m.). Time-of-day weighting factors from Table 3.4 are listed at the top of each section. Each of the four sections lists unadjusted emission rates separately for gasoline powered vehicles and diesel powered vehicles; the weighting factors from Table 3.5 are listed in the right most column. The last section of the table provides composite emission rates for each vehicle class. These represent typical daily emissions in units of grams per mile reflecting the application of the time-of-day weights and the gasoline/diesel weights.

Vehicle class weights are then applied (Table 3.6) to produce the final composite emission rates for privately owned vehicles (POV), buses, and commercial vehicles (COM). The resulting composite rates are combined as Table 4.4. Note that Table 4.4 incorporates both the PM2.5 emission rates developed here, and the NOx emissions rates developed separately.

Table 4.1 Development of Case-Specific 2010 Daily Composite Uncongested Running Exhaust Emission Factors for PM2.5
Running Exhaust Emission Factor (g/mile) 2010 Uncongested Movements PM2.5 Running Exhaust Emission Factors (grams/mile) Gas or Diesel Fraction
NB FAST Trucks NB Unladen Trucks NB Laden Trucks SB Trucks (All) NB Autos NB SENTRI Autos SB Autos (All)
Percent of Daily Activity Summer AM Peak (6-9 a.m.) 8% 20% 3% 8% 11% 11% 11% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.009 0.013 0.009 99.5%
Passenger Truck N/A N/A N/A N/A 0.011 0.015 0.010 98.5%
Light Commercial Truck 0.014 0.014 0.014 0.018 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.029 0.030 0.029 0.035 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.062 0.099 0.059 0.5%
Passenger Truck N/A N/A N/A N/A 0.181 0.225 0.172 1.5%
Light Commercial Truck 0.243 0.250 0.242 0.290 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 0.880 N/A 0.880 100.0%
Single Unit Short-Haul Truck 0.679 0.724 0.653 0.733 N/A N/A N/A 90.6%
Combination Short-Haul Truck 0.852 0.923 0.823 0.908 N/A N/A N/A 100.0%
Percent of Daily Activity Summer Midday (9 a.m.-4 p.m.) 44% 49% 42% 44% 38% 38% 38% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.009 0.013 0.009 99.5%
Passenger Truck N/A N/A N/A N/A 0.011 0.015 0.010 98.5%
Light Commercial Truck 0.014 0.014 0.014 0.018 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.029 0.030 0.029 0.035 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.062 0.099 0.059 0.5%
Passenger Truck N/A N/A N/A N/A 0.181 0.225 0.172 1.5%
Light Commercial Truck 0.243 0.250 0.242 0.290 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 0.880 N/A 0.880 100.0%
Single Unit Short-Haul Truck 0.679 0.724 0.653 0.733 N/A N/A N/A 90.6%
Combination Short-Haul Truck 0.852 0.923 0.823 0.908 N/A N/A N/A 100.0%
Percent of Daily Activity Summer PM Peak (4-7 p.m.) 23% 16% 26% 23% 16% 16% 16% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.009 0.013 0.009 99.5%
Passenger Truck N/A N/A N/A N/A 0.011 0.015 0.010 98.5%
Light Commercial Truck 0.014 0.014 0.014 0.018 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.029 0.030 0.029 0.035 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.062 0.099 0.059 0.5%
Passenger Truck N/A N/A N/A N/A 0.181 0.225 0.172 1.5%
Light Commercial Truck 0.243 0.250 0.242 0.290 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 0.880 N/A 0.880 100.0%
Single Unit Short-Haul Truck 0.679 0.724 0.653 0.733 N/A N/A N/A 90.6%
Combination Short-Haul Truck 0.852 0.923 0.823 0.908 N/A N/A N/A 100.0%
Percent of Daily Activity Summer Night (7 p.m.-6 a.m.) 25% 16% 29% 25% 35% 35% 35% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.009 0.013 0.009 99.5%
Passenger Truck N/A N/A N/A N/A 0.011 0.015 0.010 98.5%
Light Commercial Truck 0.014 0.014 0.014 0.018 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.029 0.030 0.029 0.035 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.062 0.099 0.059 0.5%
Passenger Truck N/A N/A N/A N/A 0.181 0.225 0.172 1.5%
Light Commercial Truck 0.243 0.250 0.242 0.290 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 0.880 N/A 0.880 100.0%
Single Unit Short-Haul Truck 0.679 0.724 0.653 0.733 N/A N/A N/A 90.6%
Combination Short-Haul Truck 0.852 0.923 0.823 0.908 N/A N/A N/A 100.0%
Percent of Daily Activity Occurring During Day 100% 100% 100% 100% 100% 100% 100% N/A
Summer Daily Composite
Passenger Car N/A N/A N/A N/A 0.01 0.01 0.01 Combined
Passenger Truck N/A N/A N/A N/A 0.01 0.02 0.01 Combined
Light Commercial Truck 0.04 0.04 0.04 0.05 N/A N/A N/A Combined
Intercity Bus N/A N/A N/A N/A 0.88 N/A 0.88 Combined
Single Unit Short-Haul Truck 0.62 0.66 0.59 0.67 N/A N/A N/A Combined
Combination Short-Haul Truck 0.85 0.92 0.82 0.91 N/A N/A N/A Combined

Note: Composite rates are the product of emission rate, time-of-day fraction, and gas/diesel fraction summed by vehicle type.

Table 4.2 Development of Case-Specific 2010 Daily Composite Creeping Queue Running Exhaust Emission Factors for PM2.5
Running Exhaust Emission Factor (g/mile) 2010 Uncongested Movements PM2.5 Gas or Diesel Fraction
NB FAST Trucks NB Unladen Trucks NB Laden Trucks SB Trucks (All) NB Autos NB SENTRI Autos SB Autos (All)
Percent of Daily Activity Summer AM Peak (6-9 a.m.) 8% 20% 3% 8% 11% 11% 11% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.048 0.050 0.048 99.5%
Passenger Truck N/A N/A N/A N/A 0.054 0.057 0.056 98.5%
Light Commercial Truck 0.048 0.049 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.133 0.134 0.133 0.133 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.442 0.461 0.448 0.5%
Passenger Truck N/A N/A N/A N/A 1.061 1.080 1.053 1.5%
Light Commercial Truck 1.028 1.019 1.028 1.029 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.642 N/A 2.642 100.0%
Single Unit Short-Haul Truck 1.547 1.527 1.553 1.535 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.654 1.635 1.666 1.638 N/A N/A N/A 100.0%
Fraction of Daily Activity Summer Midday (9 a.m.-4 p.m.) 44% 49% 42% 44% 38% 38% 38% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.048 0.050 0.048 99.5%
Passenger Truck N/A N/A N/A N/A 0.054 0.057 0.056 98.5%
Light Commercial Truck 0.048 0.049 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.133 0.134 0.133 0.133 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.442 0.461 0.448 0.5%
Passenger Truck N/A N/A N/A N/A 1.061 1.080 1.053 1.5%
Light Commercial Truck 1.028 1.019 1.028 1.029 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.642 N/A 2.642 100.0%
Single Unit Short-Haul Truck 1.547 1.527 1.554 1.535 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.654 1.636 1.666 1.639 N/A N/A N/A 100.0%
Percent of Daily Activity Summer PM Peak (4-7 p.m.) 23% 16% 26% 23% 16% 16% 16% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.048 0.050 0.048 99.5%
Passenger Truck N/A N/A N/A N/A 0.054 0.057 0.056 98.5%
Light Commercial Truck 0.048 0.049 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.133 0.134 0.133 0.133 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.442 0.461 0.448 0.5%
Passenger Truck N/A N/A N/A N/A 1.061 1.080 1.053 1.5%
Light Commercial Truck 1.028 1.019 1.028 1.029 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.642 N/A 2.642 100.0%
Single Unit Short-Haul Truck 1.547 1.527 1.554 1.535 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.654 1.636 1.666 1.639 N/A N/A N/A 100.0%
Percent of Daily Activity Summer Night (7 p.m.-6 a.m.) 25% 16% 29% 25% 35% 35% 35% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.048 0.050 0.048 99.5%
Passenger Truck N/A N/A N/A N/A 0.054 0.057 0.056 98.5%
Light Commercial Truck 0.048 0.049 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.133 0.134 0.133 0.133 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.442 0.461 0.448 0.5%
Passenger Truck N/A N/A N/A N/A 1.061 1.080 1.053 1.5%
Light Commercial Truck 1.028 1.019 1.028 1.029 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.642 N/A 2.642 100.0%
Single Unit Short-Haul Truck 1.547 1.527 1.553 1.535 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.654 1.635 1.666 1.638 N/A N/A N/A 100.0%
Percent of Daily Activity Occurring During Day 100% 100% 100% 100% 100% 100% 100% N/A
Summer Daily Composite
Passenger Car N/A N/A N/A N/A 0.05 0.05 0.05 Combined
Passenger Truck N/A N/A N/A N/A 0.07 0.07 0.07 Combined
Light Commercial Truck 0.15 0.15 0.15 0.15 N/A N/A N/A Combined
Intercity Bus N/A N/A N/A N/A 2.64 N/A 2.64 Combined
Single Unit Short-Haul Truck 1.41 1.40 1.42 1.40 N/A N/A N/A Combined
Combination Short-Haul Truck 1.65 1.64 1.67 1.64 N/A N/A N/A Combined

Note: Composite rates are the product of emission rate, time-of-day fraction, and gas/diesel fraction summed by vehicle type.

Table 4.3 Development of Case-Specific 2010 Daily Composite Stop-and-Go Queue Running Exhaust Emission Factors for PM2.5
Running Exhaust Emission Factor (g/mile) 2010 Stop-and-Go Queue PM2.5 Gas or Diesel Fraction
NB FAST Trucks NB Unladen Trucks NB Laden Trucks SB Trucks (All) NB Autos NB SENTRI Autos SB Autos (All)
Percent of Daily Activity Summer AM Peak (6-9 a.m.) 8% 20% 3% 8% 11% 11% 11% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.089 0.090 0.090 99.5%
Passenger Truck N/A N/A N/A N/A 0.095 0.098 0.099 98.5%
Light Commercial Truck 0.047 0.048 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.132 0.133 0.133 0.132 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.881 0.887 0.901 0.5%
Passenger Truck N/A N/A N/A N/A 1.996 2.045 2.021 1.5%
Light Commercial Truck 1.046 1.031 1.057 1.040 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.658 N/A 2.658 100.0%
Single Unit Short-Haul Truck 1.517 1.463 1.521 1.504 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.605 1.540 1.614 1.592 N/A N/A N/A 100.0%
Fraction of Daily Activity Summer Midday (9 a.m.-4 p.m.) 44% 49% 42% 44% 38% 38% 38% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.089 0.090 0.090 99.5%
Passenger Truck N/A N/A N/A N/A 0.095 0.098 0.099 98.5%
Light Commercial Truck 0.047 0.048 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.132 0.133 0.133 0.132 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel Summer Midday (9 a.m.-4 p.m.)
Passenger Car N/A N/A N/A N/A 0.881 0.887 0.901 0.5%
Passenger Truck N/A N/A N/A N/A 1.996 2.045 2.021 1.5%
Light Commercial Truck 1.046 1.031 1.057 1.040 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.658 N/A 2.658 100.0%
Single Unit Short-Haul Truck 1.517 1.463 1.521 1.504 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.605 1.540 1.614 1.592 N/A N/A N/A 100.0%
Percent of Daily Activity Summer PM Peak (4-7 p.m.) 23% 16% 26% 23% 16% 16% 16% N/A
Gasoline Summer
Passenger Car N/A N/A N/A N/A 0.089 0.090 0.090 99.5%
Passenger Truck N/A N/A N/A N/A 0.095 0.098 0.099 98.5%
Light Commercial Truck 0.047 0.048 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.132 0.133 0.133 0.132 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel Summer
Passenger Car N/A N/A N/A N/A 0.881 0.887 0.901 0.5%
Passenger Truck N/A N/A N/A N/A 1.996 2.045 2.021 1.5%
Light Commercial Truck 1.046 1.031 1.057 1.040 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.658 N/A 2.658 100.0%
Single Unit Short-Haul Truck 1.517 1.463 1.521 1.504 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.605 1.540 1.614 1.593 N/A N/A N/A 100.0%
Percent of Daily Activity Summer Overnight (7 p.m.-6 a.m.) 25% 16% 29% 25% 35% 35% 35% N/A
Gasoline
Passenger Car N/A N/A N/A N/A 0.089 0.090 0.090 99.5%
Passenger Truck N/A N/A N/A N/A 0.095 0.098 0.099 98.5%
Light Commercial Truck 0.047 0.048 0.048 0.048 N/A N/A N/A 89.5%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A 0.0%
Single Unit Short-Haul Truck 0.132 0.133 0.133 0.132 N/A N/A N/A 9.4%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A 0.0%
Diesel
Passenger Car N/A N/A N/A N/A 0.881 0.887 0.901 0.5%
Passenger Truck N/A N/A N/A N/A 1.996 2.045 2.021 1.5%
Light Commercial Truck 1.046 1.031 1.057 1.040 N/A N/A N/A 10.5%
Intercity Bus N/A N/A N/A N/A 2.658 N/A 2.658 100.0%
Single Unit Short-Haul Truck 1.517 1.463 1.521 1.504 N/A N/A N/A 90.6%
Combination Short-Haul Truck 1.605 1.540 1.614 1.592 N/A N/A N/A 100.0%
Percent of Daily Activity Occurring During Day 100% 100% 100% 100% 100% 100% 100% N/A
Summer Daily Composite
Passenger Car N/A N/A N/A N/A 0.09 0.09 0.09 Combined
Passenger Truck N/A N/A N/A N/A 0.12 0.13 0.13 Combined
Light Commercial Truck 0.15 0.15 0.15 0.15 N/A N/A N/A Combined
Intercity Bus N/A N/A N/A N/A 2.66 N/A 2.66 Combined
Single Unit Short-Haul Truck 1.39 1.34 1.39 1.38 N/A N/A N/A Combined
Combination Short-Haul Truck 1.61 1.54 1.61 1.59 N/A N/A N/A Combined

Note: Composite rates are the product of emission rate, time-of-day fraction, and gas/diesel fraction summed by vehicle type.

Table 4.4 Case-Specific Running Exhaust Emission Rates Composited Across Vehicle Classes
(g/mile)
Empty cell. NB FAST Trucks NB Unladen Trucks NB Laden Trucks SB Trucks (All) NB Autos NB SENTRI Autos SB Autos (All)
Composite 2010 Daily Uncongested Movement Running Exhaust Emission Factors for PM2.5
POV N/A N/A N/A N/A 0.010 0.014 0.010
COM 0.692 0.746 0.668 0.741 N/A N/A N/A
BUS N/A N/A N/A N/A 0.880 N/A 0.880
Composite 2010 Daily Uncongested Movement Running Exhaust Emission Factors for NOx
POV N/A N/A N/A N/A 0.31 0.47 0.27
COM 9.48 10.09 9.05 10.04 N/A N/A N/A
BUS N/A N/A N/A N/A 8.61 N/A 8.61
Composite 2010 Daily Creeping Queue Running Exhaust Emission Factors for PM2.5
POV N/A N/A N/A N/A 0.054 0.056 0.054
COM 1.416 1.400 1.425 1.404 N/A N/A N/A
BUS N/A N/A N/A N/A 2.642 N/A 2.642
Composite 2010 Daily Creeping Queue Running Exhaust Emission Factors for NOx
POV N/A N/A N/A N/A 1.08 1.19 1.15
COM 19.27 19.28 19.27 18.85 N/A N/A N/A
BUS N/A N/A N/A N/A 26.86 N/A 26.86
Composite 2010 Daily Stop-and-Go Queue Running Exhaust Emission Factors for PM2.5
POV N/A N/A N/A N/A 0.099 0.100 0.100
COM 1.379 1.326 1.386 1.368 N/A N/A N/A
BUS N/A N/A N/A N/A 2.658 N/A 2.658
Composite 2010 Daily Stop-and-Go Queue Running Exhaust Emission Factors for NOx
POV N/A N/A N/A N/A 1.99 2.22 2.27
COM 17.89 17.65 17.69 17.95 N/A N/A N/A
BUS N/A N/A N/A N/A 26.86 N/A 26.86

Case-Specific Idle Exhaust Composite Emission Factors

Time-of-day factors and gasoline/diesel fractions are applied to idle exhaust emission rates in Table 4.5. The table has a similar format to those above, with five sections corresponding to the four periods of the day (i.e., 6-9 a.m., 9 a.m.-4 p.m., 4-7 p.m., and 7 p.m.-6 a.m.) and the daily composite rate in the fifth section. However, this table lists the time-of-day weighting factors in the right hand column to make better use of available space and the PM2.5 and NOx emission rates are both presented is this one table.

Vehicle class weights are then applied (Table 3.6) to produce the final composite emission rates for privately owned vehicles (POV), buses, and commercial vehicles (COM). The resulting composite rates are combined as Table 4.6.

Table 4.5 Development of Case-Specific 2010 Daily Composite Vehicle Idle Emission Factors for PM2.5 and NOx
Idling Emission Factor (g/hour) 2010 PM2.5 2010 NOx Gas or Diesel Fraction Fraction of Daily Activity Occurring During This Period
Summer AM Peak (6-9 a.m.)
Gasoline
Passenger Car 0.140 2.99 99.5% 11%
Passenger Truck 0.074 5.15 98.5% 11%
Light Commercial Truck 0.074 6.83 89.5% 3%
Intercity Bus N/A N/A 0.0% 11%
Single Unit Short-Haul Truck 0.106 13.70 9.4% 3%
Combination Short-Haul Truck N/A N/A 0.0% 3%
Diesel
Passenger Car 2.656 37.70 0.5% 11%
Passenger Truck 5.060 113.12 1.5% 11%
Light Commercial Truck 6.147 124.93 10.5% 3%
Intercity Bus 6.680 53.92 100.0% 11%
Single Unit Short-Haul Truck 7.308 76.12 90.6% 3%
Combination Short-Haul Truck 6.894 87.44 100.0% 3%
Summer Midday (9 a.m.-4 p.m.)
Gasoline
Passenger Car 0.140 5.24 99.5% 38%
Passenger Truck 0.074 8.64 98.5% 38%
Light Commercial Truck 0.074 11.84 89.5% 42%
Intercity Bus N/A N/A 0.0% 38%
Single Unit Short-Haul Truck 0.106 13.99 9.4% 42%
Combination Short-Haul Truck N/A N/A 0.0% 42%
Diesel
Passenger Car 2.657 67.25 0.5% 38%
Passenger Truck 5.061 199.68 1.5% 38%
Light Commercial Truck 6.147 221.67 10.5% 42%
Intercity Bus 6.681 54.72 100.0% 38%
Single Unit Short-Haul Truck 7.309 77.24 90.6% 42%
Combination Short-Haul Truck 6.894 88.73 100.0% 42%
Summer PM Peak (4-7 p.m.)
Gasoline
Passenger Car 0.074 4.85 99.5% 16%
Passenger Truck 0.074 8.04 98.5% 16%
Light Commercial Truck N/A 10.98 89.5% 26%
Intercity Bus 0.106 N/A 0.0% 16%
Single Unit Short-Haul Truck N/A 13.95 9.4% 26%
Combination Short-Haul Truck N/A N/A 0.0% 26%
Diesel
Passenger Car 2.657 62.18 0.5% 16%
Passenger Truck 5.061 184.83 1.5% 16%
Light Commercial Truck 6.147 205.07 10.5% 26%
Intercity Bus 6.680 54.59 100.0% 16%
Single Unit Short-Haul Truck 7.309 77.07 90.6% 26%
Combination Short-Haul Truck 6.894 88.53 100.0% 26%
Summer Overnight (7 p.m.-6 a.m.)
Gasoline
Passenger Car 0.140 3.66 99.5% 35%
Passenger Truck 0.074 6.19 98.5% 35%
Light Commercial Truck 0.074 8.32 89.5% 29%
Intercity Bus N/A N/A 0.0% 35%
Single Unit Short-Haul Truck 0.106 13.84 9.4% 29%
Combination Short-Haul Truck N/A N/A 0.0% 29%
Diesel
Passenger Car 2.656 46.43 0.5% 35%
Passenger Truck 5.060 138.72 1.5% 35%
Light Commercial Truck 6.147 153.53 10.5% 29%
Intercity Bus 6.680 54.30 100.0% 35%
Single Unit Short-Haul Truck 7.308 76.65 90.6% 29%
Combination Short-Haul Truck 6.894 88.06 100.0% 29%
Summer Daily Composite
Passenger Car 0.142 4.63 Combined 100%
Passenger Truck 0.147 9.63 Combined 100%
Light Commercial Truck 0.696 29.87 Combined 100%
Intercity Bus 6.680 54.46 Combined 100%
Single Unit Short-Haul Truck 6.631 71.08 Combined 100%
Combination Short-Haul Truck 6.894 88.45 Combined 100%

Note: Fraction of daily activity for trucks is based on northbound laden truck activity.

Table 4.6 Case-Specific Idle Exhaust Emission Rates Composited Across Vehicle Classes
(g/hour)
Idling Emission Factor (g/hour) 2010 PM2.5 2010 NOx
Composite 2010 daily vehicle idle emission factors for PM2.5 and NOx
POV 0.14 5.65
COM 6.13 76.74
BUS 6.68 54.46

Case Specific Vehicle Start/Re-Start Exhaust Composite Emission Factors

Time-of-day factors and gasoline/diesel fractions are applied to idle exhaust emission rates via the following table:

Only composite PM2.5 emission rates are provided here. NOx emission rates were generated via a similar process; the table is available separately.

The table has a similar format to those above, with five sections corresponding to the four periods of the day (i.e., 6-9 a.m., 9 a.m.-4 p.m., 4-7 p.m., and 7 p.m.-6 a.m.) and the daily composite rate in the fifth section. Each of the four sections that correspond to the period of the day list unadjusted emission rates separately for gasoline powered vehicles and diesel powered vehicles. The gasoline/diesel weighting factors from Table 3.5 and time-of-day weighting factors from Table 3.4 are listed on the right. The last section of the table provides composite emission rates for each vehicle class.

Vehicle class weighting factors are then applied (Table 3.6) to produce the final composite emission rates for privately-owned vehicles (POV), buses, and commercial vehicles (COM). The resulting composite rates are combined as Table 4.8.

Table 4.7 Development of Case-Specific 2010 Daily Composite Vehicle Start Emission Factors for PM2.5
Empty cell. 2010 PM2.5 Start Emission Factor by Pre-Start Soak Time (g/start) Gas or Diesel Fraction Fraction of Daily Activity Occurring During This Period
Pre-Start Soak Time (minutes) <6 6 to 30 30 to 60 60 to 90 90 to 120 120 to 360 360 to 720 > 720
Summer AM Peak (6 a.m.-9 a.m.)
Gasoline
Passenger Car 0.022 0.025 0.030 0.035 0.036 0.038 0.032 0.037 99.5% 11%
Passenger Truck 0.034 0.038 0.048 0.054 0.056 0.060 0.059 0.051 98.5% 11%
Light Commercial Truck 0.028 0.031 0.039 0.044 0.046 0.049 0.047 0.042 89.5% 3%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 11%
Single Unit Short-Haul Truck 0.029 0.031 0.043 0.049 0.052 0.058 0.056 0.063 9.4% 3%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 3%
Diesel
Passenger Car 0.894 1.098 1.160 1.229 1.259 1.331 1.068 1.186 0.5% 11%
Passenger Truck 0.177 0.201 0.224 0.234 0.243 0.257 0.260 0.245 1.5% 11%
Light Commercial Truck 0.202 0.232 0.259 0.272 0.283 0.300 0.305 0.290 10.5% 3%
Intercity Bus 0.038 0.039 0.043 0.047 0.052 0.059 0.101 0.142 100.0% 11%
Single Unit Short-Haul Truck 0.034 0.035 0.039 0.044 0.050 0.056 0.085 0.148 90.6% 3%
Combination Short-Haul Truck 0.034 0.035 0.039 0.045 0.050 0.053 0.100 0.136 100.0% 3%
Summer Midday (9a.m.-4 p.m.)
Gasoline
Passenger Car 0.013 0.015 0.021 0.025 0.027 0.026 0.034 0.034 99.5% 38%
Passenger Truck 0.019 0.020 0.031 0.038 0.040 0.041 0.051 0.053 98.5% 38%
Light Commercial Truck 0.015 0.017 0.025 0.031 0.033 0.033 0.042 0.043 89.5% 42%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 38%
Single Unit Short-Haul Truck 0.013 0.016 0.029 0.037 0.039 0.043 0.052 0.056 9.4% 42%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 42%
Diesel
Passenger Car 0.709 0.833 0.955 1.041 1.079 1.053 1.231 1.204 0.5% 38%
Passenger Truck 0.105 0.115 0.146 0.162 0.172 0.175 0.226 0.261 1.5% 38%
Light Commercial Truck 0.116 0.129 0.166 0.184 0.196 0.201 0.262 0.305 10.5% 42%
Intercity Bus 0.011 0.012 0.015 0.021 0.026 0.026 0.077 0.143 100.0% 38%
Single Unit Short-Haul Truck 0.002 0.002 0.007 0.013 0.018 0.024 0.068 0.134 90.6% 42%
Combination Short-Haul Truck 0.015 0.016 0.020 0.025 0.032 0.036 0.081 0.134 100.0% 42%
Summer PM Peak (4 p.m.-7 p.m.)
Gasoline
Passenger Car 0.014 0.017 0.022 0.025 0.028 0.028 0.033 0.037 99.5% 16%
Passenger Truck 0.023 0.027 0.036 0.041 0.045 0.045 0.051 0.057 98.5% 16%
Light Commercial Truck 0.019 0.022 0.029 0.034 0.036 0.036 0.042 0.046 89.5% 26%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 16%
Single Unit Short-Haul Truck 0.018 0.013 0.033 0.040 0.039 0.046 0.054 0.058 9.4% 26%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 26%
Diesel
Passenger Car 0.746 0.875 0.987 1.025 1.095 1.085 1.186 1.269 0.5% 16%
Passenger Truck 0.118 0.141 0.162 0.172 0.186 0.187 0.220 0.272 1.5% 16%
Light Commercial Truck 0.131 0.160 0.184 0.197 0.214 0.216 0.257 0.319 10.5% 26%
Intercity Bus 0.046 0.047 0.052 0.058 0.061 0.066 0.104 0.145 100.0% 16%
Single Unit Short-Haul Truck 0.003 0.003 0.008 0.014 0.018 0.025 0.069 0.134 90.6% 26%
Combination Short-Haul Truck 0.006 0.006 0.011 0.016 0.021 0.026 0.072 0.137 100.0% 26%
Summer Overnight (7 p.m.-6 a.m.)
Gasoline
Passenger Car 0.013 0.017 0.021 0.025 0.028 0.026 0.032 0.037 99.5% 35%
Passenger Truck 0.013 0.019 0.028 0.035 0.036 0.038 0.046 0.051 98.5% 35%
Light Commercial Truck 0.010 0.015 0.023 0.028 0.029 0.031 0.037 0.042 89.5% 29%
Intercity Bus N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 35%
Single Unit Short-Haul Truck 0.006 0.010 0.020 0.027 0.029 0.034 0.042 0.046 9.4% 29%
Combination Short-Haul Truck N/A N/A N/A N/A N/A N/A N/A N/A 0.0% 29%
Diesel Summer
Passenger Car 0.697 0.905 0.931 1.020 1.102 1.021 1.178 1.271 0.5% 35%
Passenger Truck 0.073 0.115 0.137 0.150 0.153 0.161 0.203 0.254 1.5% 35%
Light Commercial Truck 0.078 0.127 0.153 0.168 0.172 0.183 0.234 0.296 10.5% 29%
Intercity Bus 0.075 0.076 0.080 0.086 0.092 0.098 0.133 0.141 100.0% 35%
Single Unit Short-Haul Truck N/A 0.001 0.006 0.011 0.017 0.022 0.066 0.132 90.6% 29%
Combination Short-Haul Truck 0.066 0.067 0.071 0.077 0.082 0.088 0.066 0.198 100.0% 29%
Summer Daily Composite
Passenger Car 0.018 0.021 0.027 0.031 0.034 0.033 0.039 0.042 Combined 100%
Passenger Truck 0.020 0.024 0.034 0.041 0.043 0.045 0.053 0.056 Combined 100%
Light Commercial Truck 0.025 0.031 0.041 0.047 0.050 0.052 0.063 0.071 Combined 100%
Intercity Bus 0.042 0.043 0.047 0.053 0.058 0.061 0.104 0.143 Combined 100%
Single Unit Short-Haul Truck 0.003 0.004 0.010 0.015 0.020 0.026 0.066 0.126 Combined 100%
Combination Short-Haul Truck 0.028 0.029 0.033 0.038 0.044 0.049 0.075 0.153 Combined 100%

Note: Fraction of daily activity for trucks is based on northbound laden truck activity.

Table 4.8 Case-Specific Stat Exhaust Emission Rates Composited Across Vehicle Classes
(g/start)
Empty cell. <6 6 to 30 30 to 60 60 to 90 90 to 120 120 to 360 360 to 720
Composite 2010 daily vehicle start emission factors for PM2.5
POV 0.02 0.02 0.03 0.03 0.04 0.04 0.04
COM 0.02 0.02 0.03 0.03 0.04 0.04 0.07
BUS 0.04 0.04 0.05 0.05 0.06 0.06 0.10
Composite 2010 daily vehicle start emission factors for NOx
POV 1.07 1.46 2.05 2.30 2.35 2.15 2.16
COM 0.36 0.48 0.78 0.86 0.85 0.82 0.81
BUS N/A N/A N/A N/A N/A N/A N/A

4.3 Case Study No-Action Alternative

The northbound passenger vehicle process at the Ysleta-Zaragoza bridge is shown in Figure 4.1 and Figure 4.2. Northbound passenger vehicles traveling into the United States from Mexico must first pay a toll on the Mexican side of the border (PN 1). Following toll collection, vehicles cross the bridge into the United States. Here, passenger vehicles are divided into one of three lane types: Standard, SENTRI, or Ready Lane. Vehicles then enter CBP primary inspection booths (PN 2). Following primary inspection processing, vehicles are either directed to exit the POE or to enter secondary inspection (PN 3). Secondary inspections include more detailed reviews of both drivers and the vehicle. Following secondary inspections at both crossing, vehicles are directed to exit the facility and are free to travel to their destination in the United States.

The northbound process for commercial vehicle movements at the Yselta-Zaragoza border crossings is shown in the Figure 4.3 aerial and Figure 4.4 flow chart. As commercial vehicles travel northbound approaching the border on the Mexican side at the Ysleta-Zaragoza crossing they must first pay a toll (CN 1). The next step is processing by Mexican customs (CN 2). Prior to processing by Mexican customs, U.S. and Mexican brokers prepare and file the Mexican Pedimento and the U.S. Inward Cargo Manifest. Transfer of these documents to the commercial vehicle operators usually occurs at a broker office in the immediate vicinity of the border crossing, on a roadside prior to the Mexican export compound, or while the truck is waiting in a queue to cross the border.

The processing by Mexican customs (CN 2) includes the verification of all documentation. Once this is complete, the commercial vehicle either is routed to the inspection facility (CN 3) or directed to bypass this and drive through the inspection area and to the exit (CN 4). Less than 10 percent of vehicles are randomly selected and are sent from the booths (CN 2) to export inspections (CN 3). The main purpose of these inspections is to ensure that all applicable export duties and taxes are paid. Export inspections may involve the partial or complete unloading of a trailer and can take anywhere from 30 minutes to several hours. Commercial vehicles arrive at the exit of Mexican Customs either directly from the entry booths or following the inspection (CN 4).

Figure 4.1 Northbound Passenger Processes Aerial

Figure 4.1 is an aerial photograph of the Ysleta-Zaragoza port of entry showing the route followed by northbound privately owned vehicles and key checkpoints that they pass through when crossing the border. Click image for text description.

Source: Cambridge Systematics, Inc., © 2012 Google, and INEGI (INSTITUTO NACIONAL DE ESTADÍSTICA Y GEOGRAFÍA).

Figure 4.2 Northbound Passenger Processes Flowchart

Figure 4.2 presents a flow chart representing the processes shown in the Figure 4.1 aerial photo. Click image for text description.

Source: Cambridge Systematics, Inc.

Figure 4.3 Northbound Commercial Processes Aerial

Figure 4.3 is an aerial photograph of the Ysleta-Zaragoza port of entry showing the route followed by northbound commercial vehicles and key checkpoints that they pass through when crossing the border.  Click image for text description.

Source: Cambridge Systematics, Inc., © 2012 Google, and INEGI (INSTITUTO NACIONAL DE ESTADÍSTICA Y GEOGRAFÍA).

Figure 4.4 Northbound Commercial Processes Flowchart

Figure 4.4 presents a flow chart representing the processes shown in the Figure 4.3 aerial photo. Click image for text description.

Source: Cambridge Systematics, Inc.

Upon exiting the Mexican Customs processes, vehicles cross the bridge and enter the United States facilities. U.S. Customs and Border Protection (CBP) primary inspection occurs at booths for designated FAST lanes, empties, or standard trucks (CN 5). FAST lanes are the two most western lanes at Ysleta-Zaragoza, with the lane adjacent to the FAST lanes primarily for empties. There is an x-ray machine right after the booth that checks the trailers while the driver drives through, getting activated by the space between the car and trailer. From the booths, the trucks are either sent to the exit (CN 7), or get directed to one of many secondary inspections (CN 6). Secondary inspections include Pylon (for FAST vehicles), VACIS, Gantry, or Eagle inspections. The VACIS inspection and Eagle inspection operate similarly. Trucks line up in a queue, drivers exit the vehicle, and a mobile x-ray unit drives along the length of the vehicles, scanning them. The Gantry is a building that trucks drive into, the driver exits, and the truck is scanned. If something is detected or the CBP officer wants to take a closer look, they are sent to the dock for further inspection. Following secondary inspection, vehicles are directed to the U.S. exit inspection (CN 7), where documentation is verified to ensure the vehicle went through all the necessary processes before being released. Additionally, U.S. DOT/Federal Motor Carrier Safety Administration (FMCSA) conduct inspections on certain vehicles following primary inspections and prior to a vehicle exiting.

Upon exiting the facility (CN 7), vehicles head to the TxDOT Border Safety Inspection Facility (BSIF) (CN 8). At the BSIF, the Texas Department of Public Safety (DPS) inspects trucks crossing into the United States using various procedures, usually starting with visual safety inspection and then proceeding to a detailed truck safety inspection if violations are found. The BSIFs incorporate ITS technologies to minimize delay at these locations, including dynamic message signs, static and weigh-in-motion scales, dimensioning in motion, and flow managers.

Northbound 2010 Activity Levels

Table 4.9 provides a summary of aggregate volume and delay data for the Ysleta-Zaragoza port of entry. The example queue length calculation results for the northbound direction in 2011 for both border crossings. Additional information was taken from Google Earth as follows:

Table 4.9 Northbound Queue and Delay Data Used for 2010
Empty cell. Ysleta-Zaragoza
Empty cell. POV SENTRI Trucks FAST
Daily Traffic Volumes (Average during hours of operation.) 6,760 836 1,022 (681 Laden,341 Unladen) 350
Length of Booth Approach Lanes 275 275 275 275
Number of Bridge Lanes 2 1 2 2
Average Daily
Open Inspection Booths 7 2 4 1
Estimated Vehicles in Queue 200 N/A 52 20
Estimated delay Empty cell. Empty cell. 25 minute Empty cell.
Calculated Queue Length (feet) (Assume average POV length + spacing = 25 feet, average truck length + spacing = 65 feet.) 1,813 N/A 1,415 788
Observed Queue Length (feet) 2,000 Empty cell. Empty cell. Empty cell.

Source: Supporting data collected from Customs and Border Protection (CBP), City of El Paso toll bridges, and traffic counts that were used to develop the Cambridge Systematics (2011) El Paso Regional Ports of Entry Operations Plan for the Texas Department of Transportation.

Calculations

A calculation summary is presented in Table 4.10, below. Inputs to the calculations include:

Table 4.10 No-Action Alternative Activity and Emissions Tabulation
Process Activity Description Quantity Units Volume NOx Rate PM2.5 Rate Units NOx Lbs./Day PM2.5 Lbs./Day
Northbound Private Vehicle Port of Entry (Mexican Jurisdiction)
Toll Collection Stop-and-Go Queue 0.05 miles 7,025 1.99 0.099 g/mile 1.54 0.08
Idle 1 minute 7,025 5.65 0.140 g/hour 1.46 0.04
Northbound Private Vehicle Port of Entry (U.S. Jurisdiction)
U.S. Primary, Buses (No transit buses utilize Ysleta-Zaragoza) Uncongested 2.95 miles N/A 8.61 0.880 g/mile N/A N/A
Creeping Queue 0 miles N/A 26.86 2.642 g/mile N/A N/A
Stop-and-Go Queue 0.05 miles N/A 26.86 2.658 g/mile N/A N/A
Idle 5 minutes N/A 54.46 6.680 g/hour N/A N/A
U.S. Primary, SENTRI Uncongested 2.95 miles 275 0.47 0.014 g/mile 0.84 0.03
Creeping Queue 0 miles 275 1.19 0.056 g/mile - -
Stop-and-Go Queue 0.05 miles 275 2.22 0.100 g/mile 0.07 0.00
Idle 1 minute 275 5.65 0.140 g/hour 0.06 0.00
U.S. Primary, General Uncongested 2.25 miles 6,750 0.31 0.010 g/mile 10.38 0.33
Creeping Queue 0.7 miles 6,750 1.08 0.054 g/mile 11.25 0.56
Stop-and-Go Queue 0.05 miles 6,750 1.99 0.099 g/mile 1.48 0.07
Idle 1 minute 6,750 5.65 0.140 g/hour 1.40 0.03
U.S. Secondary (Assumed to be 5% of general volume.) Creeping Queue 0.05 miles 338 1.08 0.054 g/mile 0.04 0.00
Restart (6-30 minute soak) N/A Empty cell. 338 1.46 0.020 g/start 1.09 0.01
Subtotal (Northbound Private Vehicle Port of Entry) 29.60 1.16
Northbound Commercial Vehicle Port of Entry (Mexican Jurisdiction)
Toll Collection Stop-and-Go Queue (FAST) 0.05 miles 350 17.89 1.379 g/mile 0.69 0.05
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.65 1.326 g/mile 0.66 0.05
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Export Customs Entrance Stop-and-Go Queue (FAST) 0.05 miles 350 17.89 1.379 g/mile 0.69 0.05
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.65 1.326 g/mile 0.66 0.05
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Export Cargo Inspection Creeping Queue (FAST) 0.05 miles 350 19.27 1.416 g/mile 0.74 0.05
Creeping Queue (Unladen) 0.05 miles 341 19.28 1.400 g/mile 0.72 0.05
Creeping Queue (Laden) 0.05 miles 681 19.27 1.425 g/mile 1.45 0.11
Restart (30-60 minute soak) N/A Empty cell. 1,372 0.78 0.030 g/start 2.36 0.09
Export Customs Exit Stop-and-Go Queue (FAST) 0.05 miles 350 17.89 1.379 g/mile 0.69 0.05
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.65 1.326 g/mile 0.66 0.05
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Northbound Commercial Vehicle Port of Entry (U.S. Jurisdiction)
U.S. Primary Uncongested (FAST) 2.95 miles 350 9.480 0.69 g/mile 21.58 1.58
Creeping Queue (FAST) 0 miles 350 19.270 1.42 g/mile N/A N/A
Stop-and-Go Queue (FAST) 0.05 miles 350 17.890 1.38 g/mile 0.69 0.05
Uncongested (Unladen) 2.7 miles 341 10.090 0.75 g/mile 20.48 1.51
Creeping Queue (Unladen) 0.25 miles 341 19.280 1.40 g/mile 3.62 0.26
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.650 1.33 g/mile 0.66 0.05
Uncongested (Laden) 2.7 miles 681 9.050 0.67 g/mile 36.69 2.71
Creeping Queue (Laden) 0.25 miles 681 19.270 1.425 g/mile 7.23 0.53
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
U.S. Secondary Creeping Queue (Laden) 0.6 miles 681 19.280 1.40 g/mile 17.37 1.26
Restart (6-30 minute soak) N/A Empty cell. 681 0.48 0.020 g/start 0.72 0.03
U.S. Customs Exit Stop-and-Go Queue (FAST) 0.05 miles 1,372 17.89 1.379 g/mile 2.71 0.21
Stop-and-Go Queue (Unladen) 0.05 miles 1,372 17.65 1.326 g/mile 2.67 0.20
Stop-and-Go Queue (Laden) 0.05 miles 1,372 17.69 1.386 g/mile 2.68 0.21
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Northbound Commercial Vehicle Port of Entry (State of Texas Jurisdiction)
Texas DPS Inspection Uncongested (FAST) 0.5 miles 350 9.480 0.69 g/mile 3.66 0.27
Creeping Queue (FAST) 0.25 miles 350 19.270 1.42 g/mile 3.72 0.27
Stop-and-Go Queue (FAST) 0.05 miles 350 17.890 1.38 g/mile 0.69 0.05
Uncongested (Unladen) 0.5 miles 341 10.090 0.75 g/mile 3.79 0.28
Creeping Queue (Unladen) 0.25 miles 341 19.280 1.40 g/mile 3.62 0.26
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.650 1.33 g/mile 0.66 0.05
Uncongested (Laden) 0.5 miles 681 9.050 0.67 g/mile 6.79 0.50
Creeping Queue (Laden) 0.25 miles 681 19.270 1.425 g/mile 7.23 0.53
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Subtotal (Northbound Commercial Vehicle Port of Entry) 186.45 13.82
Northbound Port of Entry Total 216.06 14.98

As a point of reference, the emissions also can be estimated for the same volume of traffic and assuming no border crossing delay by assuming three miles of uncongested VMT (Table 4.11). The resulting estimate assumes no toll collection or inspections of any type occur, and establishes an estimate of the floor below which no operational strategies or infrastructure investment could reduce emissions.

Table 4.11 Hypothetical Emissions Without Any Delay
Activity Description Quantity Units Volume NOx Rate PM2.5 Rate Units NOx Lbs./Day PM2.5 Lbs./Day
POV (SENTRI) 3 miles 275 0.47 0.140 g/mile 0.85 0.25
POV (General) 3 miles 6,752 0.31 0.010 g/mile 13.84 0.45
Commercial (FAST) 3 miles 350 9.48 0.69 g/mile 21.94 1.60
Commercial (Unladen) 3 miles 341 10.09 0.75 g/mile 22.76 1.68
Commercial (Laden) 3 miles 681 9.05 0.67 g/mile 40.76 3.01
Hypothetical Emissions Without Any Delay Empty cell. Empty cell. Empty cell. Empty cell. Empty cell. Empty cell. 100.16 6.99

4.4 Case Study 1 Calculation

This strategy shifts 1,000 privately owned vehicles into the SENTRI program to reduce the amount of VMT in creeping queues. Because new border crossing capacity is constructed, it is assumed that general purpose lanes will be converted to SENTRI lanes for a portion of the day, and daily average queue lengths do not change relative to the no-action alternative.

Calculations

A calculation summary is presented in Table 4.12 below. Inputs to the calculations include:

The commercial vehicle portion of the calculation table is identical to the no-action scenario. The presentation of commercial vehicle results is simplified in this example to highlight the portions of the calculations impacted by the case study strategy.

Table 4.12 POV Strategy Activity and Emissions Tabulation
Process Activity Description Quantity Units Volume NOx Rate PM2.5 Rate Units NOx Lbs./Day PM2.5 Lbs./Day
Northbound Private Vehicle Port of Entry (Mexican Jurisdiction)
Toll Collection Stop-and-Go Queue 0.05 miles 7,025 1.99 0.099 g/mile 1.54 0.08
Idle 1 minute 7,025 5.65 0.140 g/hour 1.46 0.04
Northbound Private Vehicle Port of Entry (U.S. Jurisdiction)
U.S. Primary, Buses (No transit buses utilize Ysleta-Zaragoza.) Uncongested 2.95 miles N/A 8.61 0.880 g/mile N/A N/A
Creeping Queue 0 miles N/A 26.86 2.642 g/mile N/A N/A
Stop-and-Go Queue 0.05 miles N/A 26.86 2.658 g/mile N/A N/A
Idle 5 minutes N/A 54.46 6.680 g/hour N/A N/A
U.S. Primary, SENTRI Uncongested 2.95 miles 1,275 0.47 0.014 g/mile 3.90 0.12
Creeping Queue 0 miles 1,275 1.19 0.056 g/mile N/A N/A
Stop-and-Go Queue 0.05 miles 1,275 2.22 0.100 g/mile 0.31 0.01
Idle 1 minute 1,275 5.65 0.140 g/hour 0.26 0.01
U.S. Primary, General Uncongested 2.25 miles 5,750 0.31 0.010 g/mile 8.84 0.29
Creeping Queue 0.7 miles 5,750 1.08 0.054 g/mile 9.58 0.48
Stop-and-Go Queue 0.05 miles 5,750 1.99 0.099 g/mile 1.26 0.06
Idle 1 minute 5,750 5.65 0.140 g/hour 1.19 0.03
U.S. Secondary (Assumed to be five percent of general volume.) Creeping Queue 0.05 miles 338 1.08 0.054 g/mile 0.04 0.00
Restart (6-30 minute soak) N/A Empty cell. 338 1.46 0.020 g/start 1.09 0.01
Subtotal (Northbound Private Vehicle Port of Entry) 29.48 1.12
Subtotal (Northbound Commercial Vehicle Port of Entry from No-Action Alternative) 186.45 13.82
Northbound Port of Entry Total 215.93 14.94

4.5 Case Study 2 Calculations

This strategy would combine the Mexican and U.S. cargo inspection procedures at a single facility. Such a strategy is an extension of pilot programs starting in Fall 2012 where North American imports arriving at ports in Montreal and Prince Rupert, British Columbia would be cleared for entrance into the United States without the need for a second round of inspection at the border. A modified process flow chart is provided as Figure 4.5. After the toll collection at the entrance to the border crossing, trucks would proceed to a common cargo inspection area that would operate similarly to the existing U.S. cargo screening area.

Calculations

A calculation summary is presented in Table 4.13 below. Inputs to the calculations include:

The privately owned (passenger) vehicle portion of the calculation table is identical to the no-action scenario. The presentation of passenger vehicle results is simplified in this example to highlight the portions of the calculations impacted by the case study strategy.

Figure 4.5 Northbound Commercial Processes Flowchart
Case Study 2

Figure 4.5 presents a flow chart representing an alternative scenario for how northbound commercial vehicles could be processed at the Ysleta-Zaragoza port of entry.  Click image for text description.

Source: Cambridge Systematics, Inc.

Table 4.13 Commercial Vehicle Strategy Activity and Emissions Tabulation
Process Activity Description Quantity Units Volume NOx Rate PM2.5 Rate Units NOx Lbs./Day PM2.5 Lbs./Day
Subtotal (Northbound Private Vehicle Port of Entry from No-Action Alternative) 29.60 1.16
Northbound Commercial Vehicle Port of Entry (Mexican Jurisdiction)
Toll Collection Stop-and-Go Queue (FAST) 0.05 miles 350 17.89 1.379 g/mile 0.69 0.05
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.65 1.326 g/mile 0.66 0.05
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Northbound Commercial Vehicle Port of Entry (Combined Mexican and U.S. Jurisdiction)
Combined Primary Uncongested (FAST) 2.95 miles 350 9.480 0.69 g/mile 21.58 1.58
Creeping Queue (FAST) 0 miles 350 19.270 1.42 g/mile N/A N/A
Stop-and-Go Queue (FAST) 0.05 miles 350 17.890 1.38 g/mile 0.69 0.05
Uncongested (Unladen) 2.7 miles 341 10.090 0.75 g/mile 20.48 1.51
Creeping Queue (Unladen) 0.25 miles 341 19.280 1.40 g/mile 3.62 0.26
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.650 1.33 g/mile 0.66 0.05
Uncongested (Laden) 2.7 miles 681 9.050 0.67 g/mile 36.69 2.71
Creeping Queue (Laden) 0.25 miles 681 19.270 1.425 g/mile 7.23 0.53
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Combined Secondary Creeping Queue (Laden) 0.6 miles 681 19.280 1.40 g/mile 17.37 1.26
Restart (6-30 minute soak) N/A Empty cell. 681 0.48 0.020 g/start 0.72 0.03
Combined Customs Exit Stop-and-Go Queue (FAST) 0.05 miles 1,372 17.89 1.379 g/mile 2.71 0.21
Stop-and-Go Queue (Unladen) 0.05 miles 1,372 17.65 1.326 g/mile 2.67 0.20
Stop-and-Go Queue (Laden) 0.05 miles 1,372 17.69 1.386 g/mile 2.68 0.21
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Northbound Commercial Vehicle Port of Entry (State of Texas Jurisdiction)
Texas DPS Inspection Uncongested (FAST) 0.5 miles 350 9.480 0.69 g/mile 3.66 0.27
Creeping Queue (FAST) 0.25 miles 350 19.270 1.42 g/mile 3.72 0.27
Stop-and-Go Queue (FAST) 0.05 miles 350 17.890 1.38 g/mile 0.69 0.05
Uncongested (Unladen) 0.5 miles 341 10.090 0.75 g/mile 3.79 0.28
Creeping Queue (Unladen) 0.25 miles 341 19.280 1.40 g/mile 3.62 0.26
Stop-and-Go Queue (Unladen) 0.05 miles 341 17.650 1.33 g/mile 0.66 0.05
Uncongested (Laden) 0.5 miles 681 9.050 0.67 g/mile 6.79 0.50
Creeping Queue (Laden) 0.25 miles 681 19.270 1.425 g/mile 7.23 0.53
Stop-and-Go Queue (Laden) 0.05 miles 681 17.69 1.386 g/mile 1.33 0.10
Idle 1 minute 1,372 76.74 6.130 g/hour 3.87 0.31
Subtotal (Northbound Commercial Vehicle Port of Entry) 168.08 12.48
Northbound Port of Entry Total 197.68 13.65
Updated: 12/03/2012
HEP Home Planning Environment Real Estate
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000