NMA Traffic Calming Fact Sheet ( PDF )
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By Gary Incaudo, NMA Member

We would like to share with other NMA members our experience with our City Council in attempting to alter their flagrant misuse of traffic control devices. We are a group of physicians and representatives of the American Lung Association and the Butte County Air Quality Board who came forward to ask the City of Chico to alter its current practice of traffic control.

We recognized two problems which motivated our entrance into this debate. One is the fact that Chico has one of the highest accident rates per capita of any city in the State of California. The second is a need for air pollution reduction to meet new federal guidelines and improve the quality of life in our county.

Motor vehicles use approximately one-fifth (20%) of the total daily U.S. oil consumption while traveling through signalized intersections in cities. In Butte County (where Chico is located), between 60-70% of our air pollution comes from motor vehicles. We proposed a partial solution to both of the accident and pollution problems facing Butte County. They are traffic signal synchronization, removal of unwarranted traffic signals, removal of unwarranted stop signs and traffic undulations, removal of unwarranted left-turn assisted traffic controls, placement of right-hand turn lanes and right-turn assisted signaling.

The public and our City Council seem to be under the misconception that traffic signals are, under all circumstances, safety devices. We attempted to point out that in truth, traffic signals can actually increase serious accidents and increase the frequency of traffic accidents for everyone using the intersection — drivers, cyclists and pedestrians — when installed unnecessarily and contrary to the federal MUTCD (Manual on Uniform Traffic Control Devices) standards.

This manual, or it’s equivalent, has been adopted, by statute, in all 50 states, according to our sources at the NMA. It provides guidelines established from studies performed by experienced traffic engineers. Where the guidelines were followed, traffic signals operate effectively with good public compliance and maximum public safety. At intersections where signals were installed in violation of the MUTCD guidelines, public compliance was reduced, and hazards to drivers, pedestrians, and cyclists resulted. Our City Traffic Engineers told us that of the 89 traffic signals installed in Chico, nearly 40 (45%) do not meet these standards.

A random review of accidents at recently installed traffic signals in Chico since 1990 revealed that unwarranted traffic signals either had no impact on the frequency of traffic accidents involving pedestrians, bicycles and automobiles or they actually increased accident frequency as much as 300%. Chico, as a matter of routine, installs traffic signals with left turn phasing without performing traffic-engineering studies to test if they are warranted. We were unable to find any studies that suggest that left turn phasing reduces accident rates at intersections where there has not already been an accident problem. The use of left turn phasing with all traffic signals in an attempt to reduce future accidents appears to be a fallacy. What is clear is that left turn phasing contrary to traffic engineering standards needlessly impedes traffic flow and increases fuel consumption and air pollution.

Like traffic signals, stop signs in the wrong places for the wrong reasons may actually create more problems than they solve. Numerous traffic engineering studies in cities across the United States show that arbitrarily interrupting traffic with “nuisance” or “speed-breaker” stop signs increase intentional violation and can actually increase the overall speed on the road where they are used.

Most drivers are reasonable and prudent. However, when unreasonable restrictions are continually imposed, drivers become careless or contemptuous about the need to obey the law. Unnecessary accidents and injuries can result from more flagrant violations at other intersections where the stop sign may be truly serving public safety. In such cases, the stop sign can create a false sense of security in a pedestrian and an attitude of aggressiveness or anger in a motorist. Sometimes, tragic encounters result.

For these safety reasons and others, the MUTCD strictly forbids the use of stop signs for speed control, yet this is common practice in our city. According to Chico’s Public Works department and our committee’s own investigation, Chico has placed nearly 50 unwarranted stop signs in the last four years alone (essentially ALL of the stop signs placed during that time period) in direct violation of MUTCD guidelines. The total number of unwarranted stop signs in Chico is much greater. It is estimated that well over 50% of all the stop signs in Chico do not meet MUTCD guidelines.

Another common practice by our City Council is the placement of speed bumps for speed control. However, traffic engineers tell us that speed bumps only lower the speed of traffic directly adjacent to the bump. The average speed on streets where they are installed remains unchanged. Speed bumps result in an increased risk of personal injury to bicyclists and motorcyclists. They slow down emergency vehicles approximately 15 seconds per bump, where seconds can make the difference between life and death, further risking the lives of those living in the neighborhood. Local emergency organizations such as the fire department tell us “they hate speed bumps,” especially when placed on designated emergency routes.

Furthermore, greater air pollution and neighborhood noise is created due to braking, deceleration and acceleration of vehicles. Neighboring streets now must suffer increased traffic hazards from diverted traffic trying to avoid the speed bump nuisance. The risks and the public liability they create are so great that some states (e.g. Michigan) have officially outlawed them as a standard traffic control device on public streets.

Another public misconception is that speed limits reduce vehicular speed and improve public safety. In fact, speed limits posted lower than dictated by California Vehicle Code leads to a greater risk of driver, pedestrian, and cyclist accidents. A driver’s speed is more dictated by the roadway appearance and traffic conditions than by posted speed limits. Traffic studies clearly show that reducing speed limits has no influence on vehicular speed. Unrealistically low limits cause some drivers to obey them and others to ignore them, which disrupts uniform traffic flow and increases accidents. Pedestrian and cyclists injuries increase because of their difficulty in judging the varying speed of approaching traffic.

There are six (6) streets in Chico where the posted speed limits have been set so low (and contrary to traffic engineering recommendations) that they cannot be enforced by radar because the state considers them a “speed trap”. We argued that public safety is best served by posting reasonable speed limits as dictated by scientifically based traffic engineering studies and not by public opinion. Our committee urged the City Council to remember that safety on the road comes first and foremost through using caution as pedestrians, bicyclists and drivers and not through the indiscriminate use of traffic control devices.

A significant portion of vehicular fuel consumption is wasted due to unwarranted traffic control. Traffic engineering studies have demonstrated that in cities with unwarranted traffic signals such as Chico, the fuel consumed by vehicles stopping and idling at traffic signals accounts for approximately 40% of all vehicular fuel consumption.

If our City Council followed MUTCD guidelines for all traffic control devices and listened to their traffic engineers, they could improve the efficiency and safety of traffic flow 24 hours per day, 7 days per week. The net result would be a reduction in fuel consumption, which directly translates into a reduction in county-wide air pollution. The states of Wisconsin in 1990, and Texas in 1995, published reports addressing fuel savings from maximizing signal timing. Texas, for example, found that traffic signal timing would result in an annual savings of 13.5% (20.8 million gallons) in fuel consumption, 29.6% (22 million hours) in time, and 11.5% (729 million) stops. Both of these states show a significant benefit/cost ratio in regards to fuel savings and time (over $32 saved for every dollar spent in the Texas study). These numbers would be amplified even more if unwarranted stop signs and traffic undulations were included in the calculations. The fuel consumption savings (13.5%) translates directly into significant air pollution reduction by an equivalent amount.

Our research revealed that traffic control devices in the City of Chico are frequently placed in locations and in a manner contrary to their own engineering department recommendations. We found that at times, no traffic engineering studies were requested in making decisions for the placement of traffic control devices. When requested, we were told that traffic-engineering studies were commonly ignored. We were particularly concerned as health care professionals since this action appeared contrary to the health and welfare of Butte County residents.

In approaching any city official about traffic control, it must be remembered that many of these decisions for traffic control devices are made in response to public pressure. People who purchase a home on a major thoroughfare into a neighborhood want the traffic of a cul-de-sac.

We received phone calls from bicycle advocacy groups who warned us that there are extreme groups of bicycle advocates who want no cars on the road and use cumbersome traffic control devices as their tool. It is hard for traffic engineers and city officials to argue with a public who uses such arguments as “how many people have to be killed before you do something!” even when the engineers know that what the public is asking may be actually jeopardizing public safety.

However, in many areas of popular opinion, what is accepted as “common knowledge” can exist in flagrant contradiction to known science. This is certainly true when sound principles of traffic engineering are ignored in favor of isolated public pressure or whatever “seems to make sense.” Perhaps the traffic engineers have to counter with “how many people have to be killed or injured before you quit asking us for all these ridiculous traffic control devices!” Our message to the City was that responsible governing requires that ALL available information be carefully weighed before a decision is made and that decision should reflect the best interest of ALL the citizens.

We urged our City Council to use public education as a means of countering misconceived “common knowledge” when it is false, harmful, and contrary to scientific fact. We recommended that City officials can perform a service by informing the public that: (1) traffic signals are an asset to traffic control but only if installed at intersections in accordance with MUTCD guidelines (2) stop signs are intended to help drivers and pedestrians decide who has the right-of-way and not for speed control (3) crosswalks are only for the guidance and control of pedestrians and not to ensure safety (4) lower speed limits do not slow down traffic (5) speed bumps are more hazardous than helpful on public streets, especially if a speeding problem does not already exist or on streets designated as emergency vehicle routes and (6) unnecessary traffic control devices pollute the atmosphere and waste a nonrenewable natural resource.

Several members of our committee proposed that the recent rise in “road rage” and concern for “running red lights” might be linked to the proliferation of needless traffic control devices and the so-called traffic calming techniques being used across the country. We wondered whether more rationale traffic control would solve many of these problems rather than legislating “big brother” surveillance and punishment techniques.

In our travels across the country, we have seen many cities with similar irresponsibly placed traffic control devices. We believe this to be an important NMA issue we hope other members would consider embracing in their communities. This is not an issue of saving time by driving faster. It is an issue of public health and safety as well as the right of motorists, bicyclists, and pedestrians to travel our streets without dangerous and costly impediments being carelessly imposed upon them.