Stop signs and traffic signals are placed at strategic locations to provide safe and efficient movement of the travelling public, including pedestrians. The placement of stop signs and traffic signals are governed by a set of standards outlined in a Federal Government publication: The Manual on Uniform Traffic Control Devices (MUTCD). Worcester follows the Commonwealth of Massachusetts in complying with the MUTCD.
The following are frequently asked questions and the DPW&P response.
Many studies have shown that stop signs are not an effective measure for controlling or reducing midblock speeds. Observance studies show that, when there are too many stop signs, approximately half of all motorists came to a rolling stop and 25% do not stop at all. Stop signs can give pedestrians a false sense of safety if it is assumed that all vehicles will come to a complete stop at a stop sign. Studies show that placing stop signs along a street may actually increase the peak speed of vehicles because motorists tend to increase their speed between stop signs to regain the time spent at the stop signs. Finally, the MUTCD states that "YIELD or STOP signs should not be used for speed control."
This is a common request from residents who are concerned about excessive vehicle speed in their neighborhood. They are concerned about the safety of their children and elder pedestrians.
Massachusetts Department of Transportation controls all speed limits on all public roadways in the Commonwealth. In Worcester, where the vast majority of local (neighborhood) roads fall into the category of "thickly settled" zones, the speed limit is 30 miles per hour. This speed limit is based on stopping distance and reaction time and is based on average driver response.
If there are unusual or complex conditions on your street, such as a sharp curve, it may be appropriate to request warning signs to alert drivers of the situation and suggest that their speed be appropriate for the conditions.
Schools typically have an abundance of pedestrian activities and vehicle drop-off and pick-up. Because of these conditions, the State allows for reduced speed limits adjacent to the facilities when certain warrants are met.
MassDOT warrants will allow a 20 mile per hour zone for locations where the school property abuts the public street, there is an established crosswalk and where the school has grades 1 through 9. When approved; the school zones are typically in effect during the morning arrival times, and afternoon dismissal times. A small sign, attached to the speed limit sign, notifies drivers of the times 20 miles per hour is in effect.
The warrants for School Zones are shown here, and can be viewed at: http://www.massdot.state.ma.us/Portals/8/docs/traffic/MassMUTCD20120409.pdf.
Traffic signal installation requires considerable data collection and analysis. The MUTCD lists 9 warrants for the placement of traffic signals and can be found at https://mutcd.fhwa.dot.gov/pdfs/2009r1r2/part4.pdf. The fulfillment of a warrant or warrants does not in itself justify the installation of a signal. Installing a traffic signal at a low-volume intersection can significantly increase crashes and delays. Although traffic signals can reduce the total number of collisions at an intersection, research has shown that certain types of crashes (e.g., rear-end collisions) may actually increase after a signal is installed. For this reason, the type and number of crashes at an intersection should be considered before the installation of a signal. Traffic signals can represent a public investment when justified, and cost $150,000 to $250,000 to install.
The addition of four-way stop control is an inconvenience to all the drivers using the intersection. For this reason, 3 warrants have been developed and are listed in the Manual on Uniform Traffic Control Devices (MUTCD). A four-way stop installation should only be used when traffic volumes on the intersecting roadways are approximately equal. If volumes are particularly large, a traffic signal may be more appropriate. Investigating the warrants requires an extensive traffic engineering study.
One of the multiway stop control warrants is crash related. If an intersection meets this requirement and it has approximately equal approach volumes, a multiway stop control installation may be warranted for safety purposes. However, the overall results of the traffic engineering study and the professional judgment of the engineer should also be considered. In fact, research has shown that under certain conditions other traffic control measures may be more effective and safer than the addition of a multiway stop sign. A study conducted by the City of Irvine, California, indicated that simply improving intersection visibility can sometimes be a successful approach to crash reduction at intersections.