Traffic & Safety
1. Fulfill a need,
2. Command attention,
3. Convey a clear, simple meaning,
4. Command the respect of road users, and
5. Give adequate time for proper response.
Specific warning signs for schools, playgrounds, parks and other recreational facilities where persons are gathered and may be vulnerable are listed in the Michigan Manual of Uniform Traffic Control Devices and available for use where clearly justified. The Michigan Manual has lists of traffic signs that can be used and also their proper size and installation. The Manual also describes pavement markings and their specific uses.
The warrants that receive the closest review, however, are minimum vehicular volume, interruption of continuous traffic, and accident experience. The first relates to whether there is sufficient traffic coming out of the side street in question to consider stopping traffic on the main road. The second relates to whether or not the traffic is too heavy on the main road for motorists from the side street to pull out. The last is an indication that traffic on the side street is having difficulty getting out, causing right-angle accidents to occur.
The Road Commission continuously reviews intersections for all types of traffic control devices.
Currently, regulatory speed limits are set by State Statue at a maximum 55 mph on county roads or 25 mph for business and residential districts known as “prima facie” speed limits. These speed limits are generally not posted on county roads.
Regulatory speed limits can be modified based on a unanimous recommendation from a traffic survey team consisting of representatives from the Michigan State Police, Road Commission, and Local Township. The recommendation is based primarily on results of a traffic engineering study that includes the collection of speed data, review of the crash history, and roadway characteristics.
The Lansing office of the State Police has to accept the recommendation of the survey team in order to establish a modified speed limit. Once approved, signs for the new speed limit can be posted.
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Traffic studies indicate that there is a high incidence of intentional violations where stop signs are installed as “nuisances” or “speed breakers.” The studies also show that drivers increase their speeds between unwarranted stop signs to make up for the lost time. Based on these studies and the increased speeds of drivers on streets with unwarranted stop signs, the Michigan Manual of Uniform Traffic Control Devices (MMUTCD) clearly states that “Stop signs shall not be used for speed control.”
A stop sign placed at the right place and under the right conditions, tells drivers and pedestrians who has the right of way.
The purpose of a speed bump is to make the ride over it uncomfortable for the driver, encouraging him/her to reduce their speed. With the various vehicle suspensions and wheel bases, the speed bump has shown an inability to successfully control speeds.
Speed bumps can cause maintenance problems to any vehicle and increase response time for emergency services. Because speed bumps have considerable potential for liability suits, Michigan has officially rejected them as a standard traffic control device on public streets.
The control of speeding in neighborhoods is a widespread concern which requires compliance by residents, patience and persistent effort by law enforcement – not speed bumps.
Studies have shown that this type of sign provides no evidence of reducing pedestrian crashes or vehicles speeds. Obviously, children should not be encouraged to play in the roadway. The “children at play” sign is a direct and open suggestion that it is acceptable to do so.
Federal standards discourage the use of this sign and they are not even recognized in Michigan’s traffic sign manuals. As an alternative, the Road Commission strives to remove vision obstructions to provide a safe roadway for both pedestrians and motorists.
The basic objective of a traffic control plan is to permit construction work within the county road right of way in an efficient and effective manner, while maintaining a safe, uniform flow of traffic.
The construction work and motorists, bicycles, and pedestrians traveling through the work zone must be given equal consideration when developing a traffic control plan. Each traffic control plan is developed to be consistent with the Manual on Uniform Traffic Control Devices (MUTCD).
The Road Commission relies on the cooperation of various news media in publicizing the implementation of major road closures and detours as a method of keeping the public well informed.
There are two modes of left turn signal control: permitted mode and protected mode. In the permitted mode a left turning motorist is provided either a flashing red ball or a flashing yellow arrow. The driver is permitted to turn left whenever there is an adequate gap in opposing traffic. In the protected mode a left turning motorist is provided a green arrow display while opposing traffic is stopped.
Most left turn signal operations consist of a combination of the permitted and protected modes. However, there are instances where a left turn signal is operated in the protected only mode and left turn vehicles are not given the opportunity to make a permissive left turn. The considerations for installation of a protected only left turn signal include:
- High left turn traffic volume
- High opposing through volume
- An existing crash history
- Limited sight distance
- High speed opposing through traffic
- Left turning vehicles must cross 3 or more lanes of opposing through traffic
- There are multiple left turn lanes
Note: The flashing yellow arrow is now the national standard for permissive left turn signal operation. All new left turn signal installations with a permissive mode will have the flashing yellow operation. In addition, existing flashing red balls will be replaced with flashing yellow arrows as traffic signals are upgraded/modernized.