Unrealistically low speed limits actually can lead to accidents. Numerous studies show a driver's speed is influenced more by the roadway appearance and traffic conditions than by posted speed limits. Some drivers obey posted speeds, while others ignore them, which disrupts uniform traffic flow and increases accident potential. When traffic travels at varying speeds, the number of breaks for safe crossing is reduced and pedestrians have difficulty judging the speed of approaching traffic. Posted speed limits are based on traffic engineering surveys, including a road condition analysis, accident history and the prevailing speeds of prudent drivers.
Until 1996, the maximum was 55 mph; in keeping with federal legislation allowing states to set their own limits on freeways, the Michigan Legislature enacted laws which raised the speed limit on designated rural stretches of the freeway to 70 mph. The speed limit remains at 55 mph as posted. Maximum is 25 mph in business and residential districts as posted; and in school zones when children are traveling to or from school. These speeds are not always posted, but motorists are required to know them.
Speed bumps have considerable potential for liability in Michigan and state courts have held public agencies liable for personal injury resulting from faulty design. As a result, Michigan has officially rejected them as a standard traffic control device on public streets. Moreover, tests have shown that speed bumps are physically incapable of controlling all types of light-weight to heavy-weight vehicles. Drivers of softsprung sedans are actually encouraged to increase speed for better control of their vehicle when driving over a speed bump. The best way to control speeding in neighborhoods is by persistent law enforcement, not speed bumps.
Studies show accidents and injuries actually can increase after traffic signals are installed unnecessarily. The most common results of traffic signals are a reduction in right-angle collisions, but there is a corresponding increase in total accidents, especially "rear-enders." Traffic engineers study a variety of factors, including the number of vehicles on the street, cross-street traffic, pedestrian traffic, uniformity of traffic flow and the number of vehicle stops, and possible reduction in collisions. An unnecessarily-placed signal can be a danger and annoyance to everyone using the intersection -- drivers, cyclists and pedestrians.
Obviously, children should not be encouraged to play in the roadway; "children at play" signs are direct and open suggestions that it is acceptable, according to traffic experts. Studies in cities across the nation show areas where such signs were widely posted in residential areas showed no evidence of having reduced accidents, vehicle speed or legal liability. In fact, many signs installed to warn of normal conditions in residential areas failed to achieve the desired safety benefits. The signs also can lead parents to believe they have a non-existent added degree of protection for their children.
Like traffic lights, stop signs in the wrong places for the wrong reasons actually can create more problems than they solve. Numerous studies show that arbitrarily interrupting traffic with "nuisance" or "speed-breaker" stop signs actually increases intentional violations. While studies show speed was reduced in the immediate vicinity of the new stop sign, speeds actually were higher between the intersections than they were prior to sign installation. There are nationally-recognized standards for the proper use of stop signs, based on traffic speed and volume, sight distance and the frequency of gaps in traffic allowing for safe crossing at the intersection.