Skip to contentUnited States Department of Transportation - Federal Highway Administration FHWA Home
Research Home
Public Roads
Featuring developments in Federal highway policies, programs, and research and technology.
This magazine is an archived publication and may contain dated technical, contact, and link information.
Federal Highway Administration > Publications > Public Roads > Vol. 73 · No. 4 > Practical Design

Jan/Feb 2010
Vol. 73 · No. 4

Publication Number: FHWA-HRT-10-002

Practical Design

by Joseph Jones

MoDOT emphasizes a new philosophy of doing everything well instead of a few things perfectly.

MoDOT emphasizes a new philosophy of doing everything well instead of a few things perfectly.

When rehabilitating a deteriorating bridge (above, inset) across the Missouri River, MoDOT opted to reuse the existing piers, which were in good condition. This practical design decision shaved $8 million off the price tag for total replacement. MoDOT designed and built the new superstructure (above, top) with the road closed, and a ferry provided for river crossings during construction.

When rehabilitating a deteriorating bridge (above, inset) across the Missouri River, MoDOT opted to reuse the existing piers, which were in good condition. This practical design decision shaved $8 million off the price tag for total replacement. MoDOT designed and built the new superstructure (above, top) with the road closed, and a ferry provided for river crossings during construction.

MoDOT emphasizes a new philosophy of doing everything well instead of a few things perfectly.

The Missouri Department of Transportation (MoDOT) is responsible for more than 32,000 miles (51,499 kilometers) of highways. The system is equivalent to a paved road around the equator with enough highway left over to cross the United States twice. In addition, Missouri's system includes more than 10,000 bridges.

As if normal maintenance on a system that size were not challenging enough, in the winter of 2004 MoDOT--like other DOTs around the country--faced rising oil prices, with the cost of steel and concrete not far behind. As further complications, MoDOT was forecasting serious funding shortfalls for Missouri's transportation system for the near future, and at the ballot box the public seemed to have lost interest in paying for more highway improvements. For instance, voters overwhelmingly defeated Proposition B in 2002, which would have raised the gas tax to collect money for transportation needs.

MoDOT's senior management realized that the negative economic factors on the horizon were completely beyond its control. "But MoDOT could still control how it spent the limited funds it did have," says Kevin Keith, MoDOT's chief engineer. "We could not let our commitment to the public waver, and we were unwilling to deliver anything less than we had promised."

Keith continues, "The question then became, How can we deliver a highway system that meets the needs of taxpayers and still fits within a sharply reduced budget? Soon MoDOT developed the concept of practical design: Building good projects everywhere--rather than perfect projects somewhere--will yield a great transportation system in the end."

No More Cookbooks

For years MoDOT engineers consulted a single table in a manual for most of a project's design parameters. A designer armed with an idea of what the new roadway is meant to handle in terms of design speed, functional classification, and traffic volume could check the table to determine what would have to be built in terms of typical section, maximum curvature and grade, ditch depth, minimum right-of-way, and many other features.

MoDOT only questioned the values given when they absolutely could not be followed for some project-specific reason such as slightly sharpening a curve to avoid disturbing a historic site. Then--and only then--would designers submit a design exception for a variance. Although this "cookbook" engineering produced top-shelf projects at many locations, in terms of maximizing a modest budget across an entire system, it was a recipe for failure.

For example, if a bridge over a creek could no longer carry traffic safely because of deterioration, the purpose of any improvement at that site should have been no more complicated than providing for a safe crossing. But in the past, design standards would dictate that the replacement structure be wider, higher, and longer than the one being replaced. Occasionally these increases would as much as double the size of the bridge.

As a corollary benefit, MoDOT also tended to upgrade other highway features in the general vicinity. "The attitude was almost, 'As long as we're at it . . .,'" explains Keith. In some cases MoDOT built miles of new highway alignment in the vicinity of one or two small bridge replacements.

The concept of practical design, as developed by MoDOT, points out that, in many such cases, the increase in structure size simply is not warranted. Field personnel reported that structures built as far back as the 1930s had stayed above water in all but the worst floods.

MoDOT came to question the wisdom of expanding a project when the original bridge's only deficiency was its poor structural condition, especially when the savings could be used to improve the system at another location. Also, fully upgraded, modern roadway facilities in the few miles immediately adjacent to a bridge almost seemed out of place when the remainder of the route, hundreds of miles in some cases, existed under a much older and lower standard.

In fact, MoDOT's leadership soon discovered that only five areas of work drove 80 percent of the department's construction expenditures: paving and base, 35 percent; bridges, 17 percent; grading, 11 percent; right-of-way, 10 percent; and traffic control, 7 percent. MoDOT's first 25 or so policy rewrites dealt with these areas "to get the quickest and biggest bang for our buck," Keith says.

With that in mind, Keith hit the road with a plan to completely reform the way MoDOT conducted its construction business. Well known and respected, according to colleagues, Keith was able to command attention and rally support, while other MoDOT engineers and staff drew up policy statements, publications, and other underpinnings for the new approach.

After pitching the idea to the Missouri Highways and Transporta-tion Commission during the winter of 2004-2005, Keith met face to face in the spring of 2005 with design staff in each of MoDOT's 10 districts. "Folks, I have a challenge for you," he said. "Can we look at what we are doing in the STIP [Statewide Trans-portation Improvement Program] and apply some commonsense solutions--get away from strict adherence to standards--and reduce the cost of our projects?"

Keith specifically challenged the designers to deliver their entire 5-year programs for 10 percent less money than budgeted at the time. His promise to earmark each district's savings for additional in-district projects gave designers ownership of their part of the endeavor.

To help achieve that lofty goal, Keith told the districts and the consulting community that they could put their design manuals away for 1 year and rely solely on common sense. According to Keith, these were uncharted waters for many of those listening. "This made folks nervous, uncomfortable," Keith notes. During the question-and-answer period at the St. Louis area district meeting, a consultant stood up and stated, "It sounds like you're asking us to do engineering!"

Engineering was exactly what Keith was asking for. Although he had said MoDOT design staff could shelve their manuals, he made clear they were still to adhere to three ground rules dealing with safety, communication, and quality.

Safety

Keith allowed no room for compromise where safety was concerned--every project MoDOT designed for practicality would have to be overall as safe or safer than it would have been if designed purely according to the manual. Even though some practical solutions, such as narrower shoulders or delineated bridge ends, took designers far outside their comfort zones, MoDOT still examined all solutions and weighed their consequences before adopting any solutions. "MoDOT quickly found that safety and practicality can coexist very effectively," Keith says.

In the past, MoDOT would improve locations that were deteriorating or threatening safety. For years the department had chased problems, performing safety upgrades at isolated locations only after they proved to be dangerous. "Noble enough, such efforts were not effective at improving safety," says Keith. "The nature of crashes is very dynamic--the next one might happen just a few hundred feet from an upgraded area."

Under practical design, MoDOT looks at ways to improve overall safety by making certain improvements systemwide. The approach deploys low-cost solutions over an entire system instead of a high-cost solution to an isolated problem. For example, MoDOT installed hundreds of miles of cable median barriers and rumble strips, and resurfaced 2,200 of Missouri's most heavily traveled roads using asphalt depths that were thinner than those traditionally designed for those specific areas.

For other issues, commonsense economics is the rule. If MoDOT can effectively replace a deteriorating bridge with one half its size, for instance, the agency will do so and apply the cost savings to replacing another bridge elsewhere in the highway system.

Using practical design, MoDOT rehabilitated this 15-mile (24-kilometer) segment of highway with deteriorating pavement and narrow, gravel shoulders.

Using practical design, MoDOT rehabilitated this 15-mile (24-kilometer) segment of highway with deteriorating pavement and narrow, gravel shoulders.

On this section of road, MoDOT created a smoother surface, increased visibility, and provided wider, paved shoulders, delivering the project on budget.

On this section of road, MoDOT created a smoother surface, increased visibility, and provided wider, paved shoulders, delivering the project on budget.

By following the new systemwide approach to safety, MoDOT realized a 24 percent reduction in fatal crashes between 2005 and 2008. The reduction led the Nation in safety improvement, sparing the lives of 297 motorists statewide. Further, the annual number of fatal crashes in Missouri has dropped below 1,000, down to the lowest level in 15 years, and crashes resulting in disabling injuries have decreased 7.8 percent.

MoDOT leaders are convinced the magnitude of improvements is attributable to the safety element of practical design. With no open container or primary seatbelt law having been passed in the State legislature during that period, they believe the only significant factor that could have figured into the trend must be the systemwide safety approach.

Communication

Keith's second ground rule was better communication--everywhere. MoDOT had become a better communicator in the years preceding practical design, but the goal took on even greater priority under practical design. MoDOT personnel needed to collaborate in developing every practical solution.

MoDOT improved communication channels with FHWA, the State legislature, and the public. The department asked stakeholders to help prioritize the construction program and solicited local input on solutions during design processes; it communicated all such results to State leaders, FHWA, and other stakeholders.

"The Internet is a great resource, but the institution of practical design requires a lot of face time, both inside and outside MoDOT," Keith says. "We went into this undertaking with all our cards out on the table. Nothing was done in secret."

In the past, when a district designer or project manager wished to vary from a written standard, MoDOT's central office would assume it could not be done and put the burden of proof on the designer. Under practical design, headquarters considers every idea feasible until proven otherwise. The practice of obtaining design exceptions, once strongly discouraged and infrequent, became more commonplace. This was not indicative of ineffective standards, but rather a culture shift away from the one-size-fits-all mentality.

The engineering side of MoDOT had to be careful to communicate with the legal side. Although design engineers were confident their solutions were safe, they questioned how things might be perceived in terms of liability. Early in the new paradigm, MoDOT's chief counsel informed those implementing practical design that courtroom defense actually was stronger when the defendant was shown to have exercised sound engineering judgment rather than just blindly followed standards.

Communication did not stop there. The public, at least as represented by the media, began to notice the changes at MoDOT. Outlets that for years had blasted department actions now praised them. Such headlines as "MoDOT Finds Ways To Save You Money!" and "MoDOT Success Benefits State" were not uncommon.

Quality

The third ground rule dealt with quality. MoDOT leaders told designers to be as bold and innovative as safety constraints would allow. They cautioned, however, that the practical solution had to function properly and not leave a legacy of maintenance problems. With practical design, quality remained at the forefront--it was not cutting corners as some had suggested. For instance, designers could not arbitrarily reduce a pavement thickness from 10 inches to 9 inches (25.4 centimeters to 22.9 centimeters), or reduce a corridor from 20 miles to 18 miles (32.2 kilometers to 29.0 kilometers), to attain the 10 percent cost savings. Practical design is about keeping commitments, not under-delivering solutions, Keith reminded them.

That is not to say the process was without its lessons learned. For example, an early suggested solution was to eliminate bridge approach slabs on secondary roads. Bridge approach slabs are sections of heavily reinforced pavement at bridge ends used as transitions between the relatively soft highway fill and the rigid bridge structure. Even with approach slabs in place, settlement inevitably occurs and the slabs must be lifted by pumping grout underneath them: a process known as mud jacking. Field personnel believed that for asphalt roads, the settlement at bridge ends could be mitigated more efficiently by wedging more asphalt on top of the pavement than by mud jacking below it.

Crash statistics show that in the 5 years since inception of the practical design philosophy, Missouri's highways have become safer. The downward trend in roadway fatalities reflects the ground rule that every project must become safer, and contradicts early concerns that practical design would result in unsafe conditions.

Crash statistics show that in the 5 years since inception of the practical design philosophy, Missouri's highways have become safer. The downward trend in roadway fatalities reflects the ground rule that every project must become safer, and contradicts early concerns that practical design would result in unsafe conditions."

Although the theory was sound, it failed to take into account that more secondary roads adjacent to bridge projects were being paved with concrete rather than asphalt because of MoDOT's practice of allowing alternate bids for pavement. With approach slabs eliminated from concrete pavements, settlement was not as forgiving as with asphalt. Over time, the rigid nature of the pavement allows it to bridge the settling earth. But being nonreinforced, when enough of its support disappears, it can crack, suddenly and severely.

Keeping quality in mind, engineers quickly retooled the standards and developed a modified bridge approach slab for secondary roads. The slab was thinner and contained nearly half the steel of a conventional approach.

Results

After 1 year under practical design, the results of Keith's challenge to the districts were better than expected. Redesigned projects showed an aggregate savings of 13 percent in the 5-year plan. MoDOT had saved nearly $400 million across a $3.1 billion program. Within weeks of confirming that success, MoDOT reinvested nearly one quarter of the savings in projects that previously it could not afford.

The practical design approach did not end there; in fact, it was just beginning. After the design staff's year of adopting the new approach, a large cross section of the designers assembled for a daylong facilitated brainstorming session. MoDOT officials with a newly formed engineering policy group asked the designers to talk about their experiences with practical design: what had worked well and what had not. This query elicited about 400 individual comments about existing policies, and these comments were collected and eventually refined into 22 areas that were the most likely to yield savings if changed. On the heels of that meeting, MoDOT's senior management team held a 2-day retreat and reconstructed those policies to maximize value.

The results were newer, more flexible policies that MoDOT leaders wrote into a revised manual. In place of black-and-white recipes for roads, the new manual includes ranges of solutions that depend on the context of projects. For instance, where the old design table called for all lanes to be 12 feet (3.7 meters) wide, the new guide allows lanes as narrow as 10 feet (3 meters) depending on location and volume. Where traditional design methods specified a minimum right-of-way width, practical design policies prescribe the bare minimum needed to contain the earthwork. "Soon design staff throughout MoDOT were using the new manual to guide them toward value instead of inflated design," says Keith.

Since 2002, the department has delivered more than $8.5 billion worth of work and has done so 0.3% under budget. "More important, design staff have acquired a taste for practicality and routinely push the envelope in favor of innovation," says Keith.

MoDOT engineers found that this low-volume bridge maintained high ratings for its super- and substructures, so they opted to replace just the deck.
After meeting with local farmers, MoDOT engineers designed this wider bridge deck with a low-profile railing to accommodate passage of farm equipment.

(Top) MoDOT engineers found that this low-volume bridge maintained high ratings for its super- and substructures, so they opted to replace just the deck. After meeting with local farmers, the engineers designed a wider bridge (Bottom) with a low-profile railing to accommodate passage of farm equipment.

Leadership Support Is Critical

Successful establishment of the practical design program was no accident. Among a handful of implementation factors, the most important without question was leadership. Organiza-tional change of this kind must be a top-down undertaking, according to Peter Rahn, MoDOT's director.

"We will be bold. We will be willing to experiment," Rahn had said early on. "We will not fear failure. We will be determined. We will attack problems."

A radical change in everyday culture will not endure long if implemented only at the grassroots level. But, if the very top tier of leadership believes in the philosophy, defends it, and tenaciously pursues it, the chances of success become very good, MoDOT learned.

A strong spirit of openness also was crucial to practical design's success. In an environment of change, MoDOT found value in designers and decisionmakers considering all innovations, no matter how new or how far from the conventional.

At the same time, an organization must be willing to accept some ideas that are not open to discussion. In some cases, leadership might have to introduce nonvoluntary actions necessary to guide a program. For example, MoDOT leaders mandated divisional reorganization and a single engineering policy group to handle standards for the entire agency.

According to Keith, a favorable political environment is certainly an advantage, but the practical design philosophy can thrive even in a chilly atmosphere. Crucial in all circumstances, transportation leaders must work closely with State and Federal government leaders, not in spite of them. MoDOT took care to work hand-in-hand with the Missouri Division of the Federal Highway Administration (FHWA) while developing practical design.

"We embraced the practical design concept, but we didn't always agree with their approach to everything," says Assistant Division Administrator Edgardo Cordero, of FHWA's Missouri Division. "We always worked closely with them and usually found ourselves in a place that was suitable to both of us. Well implemented, this practical design approach should be a win-win situation for all."

Survey Says . . .

Missouri has earned its nickname the Show-Me State: Residents seem to be skeptical of new ideas, especially those that seem too good to be true. No surprise then that public apprehension arose when MoDOT promised a world-class transportation system in the face of a looming economic crisis. "But before long, practical design's success was undeniable," says Keith.

MoDOT tracks customer confidence as one of its measures of success. Today, 95 percent of Missouri citizens believe the department's completed projects are the right transportation solutions.

Joseph Jones, P.E., is the engineering policy administrator for MoDOT and is responsible for developing and publishing the State's transportation standards. In 2005, MoDOT's leadership charged him to implement practical design as the agency's business philosophy. He graduated from the University of Missouri-Rolla (now known as Missouri University of Science and Technology) with a B.S. in civil engineering in 1992.

For more information, contact Joseph Jones at 573-751-3813 or joseph.jones@modot.mo.gov.

ResearchFHWA
FHWA
United States Department of Transportation - Federal Highway Administration