Agenda - Council - 05/26/1998 - Laserfiche WebLink

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I I I I I I I I I I I I I I I I A video presentation Traffic Control: What works? Introduction: This is a 14-minute video presentation by the Minnesota Local Road Research Board. Its objective is to offer information on how public officials develop ~easonable, research-based traffic .:ontrol strategies and choose traffic control devices. A common response to a serious accident is a request for a STOP, YIELD, or a lower speed limit sign at the site. However, FHWA report FHWNRD 81/084, entitled Stop, Yield and No Control at Intersect- ions states that trying to increase the amount of control at an inter- section with signs usually doesn't bring the desired results. In fact, the report shows that intersections with no control and those controlled by YIELD signs actually had lower accident frequencies than those controlled by STOP signs. Determining the best type of traffic control for a given situation is one of the most complex tasks faced by our public engineers. But, through many decades of research and experience, engineers have dev- eloped reliable methods for control- ling Iraffic on our streets and roads. · Research shows Ihat consistent tralflc control is essential. If inter- sections with similar conditions in terms ct visibility and traffic are posted wilh Ihe same signs and have the same speed limits, drivers can develop consistent habils and can have greater confidence in predicting olher drivers' actions. · Some signs that do not state specific rules for drivers, such as "Watch lot Children," can lead to inconsistent responses. Some slow down; others don'l. Meanwhile residents develop a false sense of security. Inconsistency on IhePart of motorists and reduced vigilance on the part of residents is also a formu!a for trouble. · Transportahon engineers consider Ihe enlire system of streets - rather than jusl a single intersection - in choosing traffic control devices. Traffic control in one location affects nearby locations. · Because individual silualions have individual characterislics, the decision to use or no', use particular devices at a Iocalion should be made on the basis ol an engineering study. Every sludy should consider at leasl four essential factors: traffic speed, traffic volume, sight distances, and accident history. STOP vs YIELD signs: Improper use of STOP signs breeds contempt for STOP signs in general and for the public officials who installed the signs. Another way to look at the ef- fect of the STOP signs is to see that we have increased the range of drivers' responses. A few cars come to afu,. stop; most slow down to one degree or another: and some don'l slow dc.'.*n at all. Since the range of resoonses has increased, we have mace it more difficult to predict what any individual driver will do. The federal study referred to earlier shows thai. at inlersections of local streets '.'.'~th Iow traffic volumes and good sig!t: lines, only about one out of live drivers will actually come to a comolete stop for a STOP sign. So. 80 percent of the drivers who ::-~ss through an inter- seclion ,,vi~l; STOP signs are now law-breakers YIELD signs tell drivers to make their own decisions about how to deal with the situation. When the drivers on the busier road know that cross traffic is controlled by a YIELD sign, they will be more likely to drive de- fensively and less likely to trust that the cross traffic will stop for them. Speed Limits: The safest situation is for all vehicles in traffic to be traveling at a uniform speed. Speed limit signs will help to achieve that goal as long as the posted limit is one that most drivers find reason- able. So it's important to post con- sistent speed limits throughout the state. That's one reason why, in Minnesota, our regulatory speed limits can only be established by the State Commissioner of Transportation. Summary: Public agencies will find that they put themselves in the best legal position when they follow these guidelines. Officials should arrive at a systematic and system- wide traffic control policy and should then establish a track record of following that policy. The policy should state that decisions about specific locations will be based on research that takes traffic speeds. traffic volumes, sight distances, and previous accident history into account. This video was produced by Braun Interlec Corl:X:~'alion. for the Research ,.mplemonla=;cn CommiMee of the M~nnesola Local Raod Research Board. For more informalon LRRB. conlacl lhe Mn/DOT Off:ce o! Res.ea.:~ Adminislrabon al(612) 282.2274 Cop,es ot. ceo can be obtained Irom lt~e Off,ce o: Rosea,c- Administfabon or can be loaned from the Transporlal~on Ubraries a', (6 ~ 2i 2~3-2385