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Sensitivity Matrix

IV(a) Temperature - Summary

Asset Categories   Temperature - Summary
Mode Sub-Mode Important Impact-Asset Relationships Threshold Mobile-Specific Detail Potential Indicators of Sensitivity
Bridges Bridge (Superstructure) Bridge pavement may exhibit similar sensitivities as road pavement. See "Paved road surface" sub-mode for more detail. Bridge pavement may exhibit similar sensitivities as road pavement. See "Paved road surface" sub-mode for more detail. Bridge pavement may exhibit similar sensitivities as road pavement. See "Paved road surface" sub-mode for more detail. Bridge pavement may exhibit similar sensitivities as road pavement. See "Paved road surface" sub-mode for more detail.
Bridge (Substructure)        
Operator Houses (movable bridges) and electrical parts        
Roads and Highways Paved road surface Sustained high temperatures can cause asphalt concrete pavement to soften resulting in rutting and shoving. Concrete pavement can heave at the joints. When high heat is accompanied by drought conditions, asphalt concrete pavement can crack making it more vulnerable to water when it does rain. [65] Thresholds vary depending on pavement design. In Mobile, pavement binder may exhibit sensitivity beginning at 108 F, particularly if combined with truck traffic. [61] Mobile County currently does not experience a lot of damage due to pavement softening. However, during extreme heat spells where the temperature can remain above 100 F, with relatively little cooling at night, the pavement can soften. Areas with high truck traffic (particularly areas where trucks stop) can experience shoving during heat spells. [43] Although aggregate is not sensitive to temperature, it can influence the sensitivity of the overall hot mix asphalt paving. For example, more angular aggregate may help to prevent rutting, which can result from high temperatures. [65, 5]
Road substructure (gravel base, substructure) No documented relationship. None. No documented relationship. No documented relationship.
unpaved roads No documented relationship. None. No documented relationship. No documented relationship.
Stormwater drainage (culverts, side drains, etc) No documented relationship. None. No documented relationship. No documented relationship.
Highway, road and street signs and traffic lights No documented relationship. None. No documented relationship. No documented relationship.
Highway and road traffic and service High temperatures can increase health and safety risk as well as engine and equipment heat stress for road maintenance, truck operations, bus operations, private vehicles, and public vehicles. [49] Health and safety risk as well as possible engine/equipment heat stress begins at around 85F, but the situation becomes more critical at 105-110F. Restrictions limiting the number of hours that road crew maintenance can work begin at 85F. At 110F, operations are generally restricted. [49] Information not available. No documented sensitivity indicators.
Railroads Electrical Equipment (gates/flashers and signal bungalows) Possible malfunctions of track sensors and signal sensors above threshold temps. [49] Worsening threats >= 90 °F. [49]    
Railroad Tracks, Ties, and Ballast Increases in temperature lead to increased risk of buckling and expansion. Rail damage can lead to increased risk of hazardous materials spills. In cold weather, Continuous Welded Rail (CWR) contracts. This can cause fractures which result in rail separations. [49, 57, 2, 54, 8, 60] 110°F cited as threshold for buckling. [49]
At 90°F, rail speed is slowed. [2]
Days above 90°F and 100°F are expected to increase in the Gulf Coast region. [60] Increased number of track signal warnings
Railroad services (i.e., operations) Buckled tracks remove line from service, at least temporarily. Threat of heat damage reduces travel speed, which reduces efficiency.
In Winter, cold can result in brittle track, leading to increased risk of track breakage, as well.
Additionally, the risk of heat exhaustion among rail crew increases. [2, 57, 8, 60, 49]
Heat index >= 105 °F [49] Days above 90°F and 100°F are expected to increase in the Gulf Coast region. [60]  
Airports/ Heliports Runway and navigational aids Higher temperatures decrease air density, which means that planes need more runway space in order to take-off. Extreme heat may cause "heat buckling of runways." [6, 48, 60] In high elevation airports, a 1-2% decrease in density may increase the number of days per year that airports operate under limited service. [54, 24, 60]   - Elevation of airport
- Length of runway and type of aircraft traffic
Aircraft        
Airfield buildings and structures (e.g., terminal buildings, hangers, air traffic control tower) Greater need for cooling, HVAC systems in terminals. [6] No documented threshold. No Mobile-specific information available. No documented sensitivity indicators.
Services and airport/ heliport operations (e.g., flight departures and arrivals, baggage/cargo transfers, ground transportation) Extreme high temperatures may limit the types of aircraft that can take off on certain days, or pilots may have to adjust cargo or passengers to lower weight. [6] Reduction in aircraft lift as temperatures increase. [48] No Mobile-specific information available. No documented relationship.
Natural Oil and Gas Pipelines Pipelines, aboveground No documented relationship. No documented relationship. No documented relationship. No documented relationship.
Pipelines, underground No documented relationship. No documented relationship. No documented relationship. No documented relationship.
Pipelines, offshore No documented relationship. No documented relationship. No documented relationship. No documented relationship.
Aboveground infrastructure (e.g., compressor stations, metering stations, other buildings, structures) No documented relationship. No documented relationship. No documented relationship. No documented relationship.
Utilities for pipelines - electricity No documented relationship. No documented relationship. No documented relationship. No documented relationship.
Electric Power Systems Electric Power Systems Increased demand for air conditioning can stress electric power systems during heat events. No threshold documented. None. Unknown.
Marine Ports, Terminals, and Waterways Electrical Equipment No documented relationship. No documented relationship. No documented relationship. No documented relationship.
Terminal Buildings Pavement around structures could buckle. See "Paved road surface" threshold information. None. See "Paved road surface" threshold information.
Channels No documented relationship. No documented relationship. No documented relationship. No documented relationship.
Piers, wharves, and berths Paved piers could be susceptible to surface buckling. See "Paved road surface" threshold information. None. See "Paved road surface" threshold information.
Port services (i.e., operations)        

*Note dollar amounts are not adjusted for inflation.

Updated: 03/27/2014
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