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Traffic calming and the battle for the roadway

By: staff

Date: Thursday, 24. December 2009

"It looks like they're designing more and more streets with 4 X 4s in mind."
-- Motorist

Many North American drivers have never heard of "traffic calming", but it's a term they will become increasingly familiar with in the near future. In Europe, calming has been around for a while, particularly in the Netherlands, Denmark and Germany, which implemented schemes as early as the 1970s. It's a growing trend in North America.

traffic calming Put simply, calming is a strategy of adding design features to roadways that cause drivers to slow down. The features include such devices as speed bumps, lane narrowing, center islands, raised portions of pavement, streetscaping (trees, hedges, etc.), and regulatory signs*. Amongst people raised on automobility, and hooked on its speed and convenience, it is not surprising that many drivers regard calming as a major irritant. In some quarters it is characterized more as a plot against drivers than a legitimate road safety strategy.

Looked at in a positive light, calming provides drivers with the cues they need to adjust their speed to a particular road environment. Looked at negatively, it's a territorial tactic by neighborhoods to keep other drivers out. As traffic density grows and the battle for roadway territory and rights intensifies, calming will undoubtedly be the focus of increasing debate.

What traffic calming does

It will help this debate if all the parties involved understand the principles behind traffic calming. Research evidence shows that most drivers adjust their speed more readily in response to road and traffic conditions than to speed limit signs and the often remote possibility of enforcement penalties. Roadway features such as narrow lanes, certain kinds of road markings, bridge abutments, hidden areas, surface problems and traffic activity result in fairly predictable reductions in speed, whereas a 25 mph (40 km/h) speed limit on a wide open four-lane road will bring in a rich harvest of speeding-ticket revenue if police choose to enforce it.

The "85th percentile" method of setting speed limits (according to the speed normally adopted by 85% of drivers) is based on observations that 85% of drivers tend to adopt a sensible speed for prevailing road conditions.

A roadway that lacks the kinds of cues mentioned above tends to have faster traffic. In urban residential and business areas, the removal of physical clues to appropriate speed can create a sort of self-fulfilling prophecy in which faster traffic banishes competing activities from the road space and street life diminishes. A good way to get rid of street life is to make the street one-way, and clear away physical obstacles such as center islands, bollards and traffic lights.

The fact that drivers go faster on more open roads is not because they are all uncaring or contemptuous of the rights of others. They usually have other things on their minds and unconsciously respond naturally to the physical cues presented to them. Drivers have long argued that low speed limits on a roadway that is straight and wide open are unfair because they invite speed and then penalize drivers with enforcement and fines. A 25 mph (40 km/hr) speed limit on a street that has space for four lanes, and few obstacles to faster speeds, is little more than an unfair means of taxing drivers, these motorists will say, and they have a point.

Advocates of higher speed limits will argue that drivers are capable of managing their speed and that higher speed does not cause crashes. They can quote research to back their claim. However, safety and lack of crashes are not the same thing. If faster traffic does not have greater crash rates (the evidence is mixed on this) it may not be because faster traffic is just as safe, but rather because pedestrians, cyclists, children, animals, and even slower drivers have been frightened off roadways used by faster traffic. By way of example, an elderly pedestrian will have great difficulty crossing a four-lane roadway on which the speed limit is 40 mph (60 km/hr) and some vehicles are traveling at 70, 80 or even more. Elderly pedestrians will simply avoid crossing, and perhaps even be forced to avoid the entire area.

A benign way of looking at calming is that it offers a better way of letting drivers know about the activities (or needs, if that's a better way to put it) of other road users in a particular area.

The negative view

Looked at negatively, calming is seen as a means of thwarting drivers in their efforts to get from A to B. An article on the National Motorists Association's web site describes calming as "simply a device to put a favorable spin on tactics used to obstruct, divert and slow traffic."

Proponents of these tactics, says the NMA, "are usually persons who live along urban or suburban streets and object to motor vehicle traffic passing by their homes. The NMA web site offers a guide for beleaguered motorists who feel they are victims of such tactics and wish to actively fight them.

The NMA guide makes some points in its list of arguments against calming. In addition to increasing vehicle wear and tear, air pollution, and noise, "braking and accelerating in response to speed bumps, speed, stop signs, and traffic signals increases fuel consumption and emissions. This can contradict other efforts to reduce emissions and contribute to a community becoming or remaining a 'non-attainment' air quality zone, thereby being subjected to federal mandates and restrictions, increased response times for emergency vehicles and increased street maintenance costs," says the article.

The NMA may have a better point when it suggests that calming techniques such as speed bumps, obstacles and narrowed lanes simply serve to shift traffic problems to other streets. Calming can easily become a neighborhood politics issue in which groups simply assert control over their territory at the expense of others.

A better strategy, the NMA suggests, is to encourage traffic to move to major streets by "raising speed limits, synchronizing traffic lights, removing four-way stop signs, and improving access to roadside businesses" on these streets. This, suggests the NMA, can be presented to planners as a win-win solution. However, it's naive of the NMA to suggest that volume of traffic is the only problem and that providing fast arterial roadways will restore safety on neighborhood streets. Some drivers will still speed at rates that make life dangerous and uncomfortable for other street users. This motoring trait is exacerbated by modern cars that provide power and acceleration while using hi-tech suspension and handling features to mask the physical feedback that speed normally brings. Drivers who are unschooled in the effects of what they do, and the rights of other road users, add greatly to the problem.

In opposition to the NMA's unqualified support of drivers is an increasing desire on the part of communities to create friendly environments in which street life, with its many facets, can thrive, and livable neighborhoods flourish. In many ways it's a desire to return to the days before automobiles devastated urban life and suburban shopping malls became the only communal people-places available to dispersed populations of auto-mobile citizens living in bleak expanses of detached housing.

What's at stake

There's no doubt that the battle for rights on the roadway is going to heat up. Environmentalists have pointed out that making roadways more efficient for automobiles encourages reliance on automobile transportation as opposed to mass transportation. Improving a highway with better surfaces and extra lane space makes it easier and more economical for drivers to use their cars to commute, and harder for public transit to compete. And the extra lanes fill up as drivers factor the extra convenience into their commuting calculations, so traffic congestion problems are not resolved.

The stakes in the roadway battle are quality of life, rights of different road users, effects on the environment, the automobility and convenience most of us are addicted to, and the frustration and rage that can surge to the surface during conflicts for space and rights.

The NMA and other advocates for the automobile lose credibility when they ignore the larger issues and claim, as the NMA does, that traffic calming advocates are invariably local residents who use "a collection of politically correct excuses" such as "it's for the children" to keep other traffic off their streets. Drivers are going to have to look beyond selfish concerns in order to remain a credible influence on the future of traffic management. This means understanding the principles of traffic calming, knowing what's at stake, and providing reasoned input rather than a knee-jerk reaction to anything that impedes their speedy passage along roadways.

* " Traffic Calming and Low-Speed Urban Street Design " by Christopher Poe (Pennsylvania Transportation Institute, Pennsylvania State University, Research Office Bldg., University Park, PA 16802)(Dec. 4-6, 1995)[TD100:PA95-9512]

Further comments to this article have been disabled.

All Comments (3)

Showing 1 - 3 comments

Lyle Logan,

I have an even better idea: Let's just go tell the entire collective of effeminate busy-bodies who are trying to solve problems by trying to micro-manage how and when we drive our cars to collectively sod off and mind their own GD business?

Traffic Safety Store,

Great article Chris. We actually also try to offer resources on traffic calming solutions and news, here is an example


The problem with speed and speeding is that is not a solution. Any calculations by anyone will show that speeding between red lights or stop signs is just wasteful not time efficient. Some speeders complain when they get a citation that is is expensive. Fact of matter, speeding in itself is very expensive usually at about $300 to $500 dollars a year. Can U afford that each year?

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