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HomeMy WebLinkAbout03-05-18 Public Comment - R. Zimmer (on behalf of the PTS Committee) - I-90 Speed LimitFrom: Robin Crough To: Agenda Subject: FW: City Advisory Board Recommends Lowering I-90 Speed Limit Date: Monday, March 05, 2018 8:15:47 AM From: Ralph Zimmer [mailto:RalphZimmer@mcn.net] Sent: Monday, March 5, 2018 7:23 AM To: Cyndy Andrus <CAndrus@BOZEMAN.NET>; Chris Mehl <CMehl@BOZEMAN.NET>; Jeff Krauss <Jkrauss@BOZEMAN.NET>; I-Ho Pomeroy <IPomeroy@BOZEMAN.NET>; Terry Cunningham <TCunningham@BOZEMAN.NET> Cc: Andrea Surratt <ASurratt@BOZEMAN.NET>; Craig Woolard <CWoolard@BOZEMAN.NET>; Richard Hixson <rhixson@BOZEMAN.NET>; Steve Crawford <SCrawford@BOZEMAN.NET>; Richard McLane <RMcLane@BOZEMAN.NET>; Josh Waldo <JWaldo@BOZEMAN.NET>; Robin Crough <RCrough@BOZEMAN.NET>; Danielle Scharf <DScharf@sandersonstewart.com>; Mandee Arnold <MandeeMT@gmail.com> Subject: City Advisory Board Recommends Lowering I-90 Speed Limit Monday, March 5, 2018 Mayor Andrus and Bozeman City Commissioners, I am writing on behalf of the Bozeman (Area) Pedestrian and Traffic Safety Committee, the City's Advisory Board on ground transportation matters and particularly on traffic safety matters. At its meeting this evening, the City Commission will be considering one of those matters, namely the proposal to request the State to lower the I'-90 speed limit to 65 MPH in the vicinity of Bozeman PTS voted on both December 13 and February 14 to recommend that the I-90 speed limit in the Belgrade/Bozeman area be lowered to 65 MPH. Both votes were unanimous. It is a safety matter. There Are SEVERAL, NOT "Just" One, Safety Concerns One safety concern has received a fair amount of attention in the media, namely the safety of emergency personnel responding to incidents on I-90. I have seen the statistics and they are eye-opening. The three fire departments (Central Valley, Bozeman, and Fort Ellis) are called to incidents on I-90 about three hundred times a year! These are crashes, vehicle fires, hazardous material spills, grass fires, etc. Law enforcement personnel are there additional times making traffic stops,etc Given the high volumes and the existing 75 MPH speed limit, , these incidents present a real hazard to those public safety personnel and their equipment. It truly is a work place safety issue. However, there are other safety issues not involving such incidents and these other issues are also very important. One of these is "stacking". This occurs when the exit ramps are so backed up that vehicles wishing to exit must slow significantly and sometimes even stop before leaving the through lanes on the Interstate. This results in a lot of lane changes and weaving operations, all of which are hazardous at the high speeds and high volumes on the Interstate. There is risk of rear-end and sideswipe crashes. The relative high speeds in the through lines leaves less time for drivers to find the gaps needed to safely change lanes. High volumes and high speeds are a deadly combination High volumes result in fewer and shorter gaps for changing lanes in order to pass, to get to an exit ramp, or to avoid "stacking". The higher the speed, the riskier is the diversion of the motorist's attention as they look for gaps in the adjacent lane and the more disastrous are any resulting crashes. Because of less than desirable horizontal and vertical geometry, the westbound entrance ramp onto I-90 at the East Main interchange is undesirably hazardous. Safety would be increased if westbound through traffic at that interchange were traveling at a lower speed. There are other safety benefits that would occur if the speed limit were dropped to 65 MPH and that lower limit extended further east and west than the city's jurisdictional area All of the safety concerns mentioned above are exasperated by the combination of high volumes and high speeds. The Montana Department of Transportation's own data shows that the volumes on I-90 in Bozeman rival or perhaps even surpass those of Billings, and those volumes far surpass those in Butte, Great Falls, and Missoula Those volumes in Bozeman are growing rapidly and there is not much that can be done to reduce them The speed limit, on the other hand, is something that within reason can be controlled 65 MPH would be much better than 75 MPH,. Billings, Butte, Great Falls, and Missoula all presently have 65 MPH speed limits Bozeman doesn't. Apples & Oranges There is a State law that mandates that motorists approaching an emergency incident on a highway must slow down by 20 MPH and, if possible, move over into the adjacent lane. Some people have said that the 65 MPH speed limit is not needed because that 20 MPH reduction requirement means vehicles will be passing those emergency incidents at only 55 MPH and 55 is even less than 65. That is an invalid comparison. It is comparing apples to oranges. It would be valid to compare the posted speeds (75 ms 65). It also would be valid to compare the allowable speed when passing an emergency incident (55 vs 45). The conclusion is inescapable. Lower speeds would result from lowering the posted speed limit from 75 down to 65 MPH. Safety would be increased by lowering the existing posted speed limit. A Traffic Engineer Responds to Commissioner Krauss If the speed limit for passenger vehicles were lowered to 65 MPH, the assumption is the speed limit for trucks would also be 65 MPH. At the October Transportation Coordinating Committee (TCC) meeting, Commissioner Krauss said he would only be willing to support reducing the posted speed to 65 MPH if the speed limit for trucks were reduced to something under 65 MPH. I suspect that is still his position and I would like to give a traffic engineer's response to that position. Everything else being equal, traffic engineers like to have both uniformity in driving speeds and consistency in speed limits. Both contribute to safety. If every vehicle driver chose to drive at exactly the same speed, there would be no passing and no lane changes (except as needed on entering or leaving the highway). Differential speed limits are passenger vehicles and trucks are defensible if traffic volumes are relatively low and thus there are numerous and lengthy gaps for passing. As mentioned above, we have high, not low, volumes on the Interstate in Bozeman. Consistency and predictability in speed limits is desirable. Passenger vehicle drivers in Montana know that the Interstate speed limit in Billings, Butte, Great Falls, and Missoula is 65 MPH and thus they would not be surprised to find that the speed limit in Bozeman is also 65 MPH. Similarly, truck drivers in Montana know that their speed limit in those other four Montana cities is 65 MPH and thus they would expect it to be 65 in Bozeman Plus the speed limit for trucks would remain 65 MPH both in those Montana cities and outside those Montana cities thus giving truckers consistency and predictability. Also, if a passenger vehicle wanted to exit the interstate at some particular interchange and if the speed limit for trucks were lower than for passenger vehicles the trucks would tend to create a moving fence making it more difficult and more hazardous for them to get into the right hand lane to reach the exit ramp. Why JUST a Temporary Speed Reduction? It appears the quickest and easiest way to get the speed limit lowered to 65 MPH would be by getting the State Transportation Commission to exercise its authority to set a "temporary reduced speed limit" of 65 MPH , so that is the route we are encouraging. The 65 MPH speed limit would be posted and there would be no indication to the motorist that it is a "temporary" speed limit The speed limit would remain "temporary" until at some future date the State Transportation Commission either made it permanent or revoked it. That decision would be based on an "engineering and traffic study" to be done by the Montana Department of Transportation It conceivably might take years before that decision was made. The reduced speed limit on the Interstate in Butte took eight years to be changed from "temporary" to "permanent". Personally, I would be glad if that determination in Bozeman were postponed until after the 2020 census results were known. Those results plus traffic volumes that undoubtedly will have grown even larger would increase the probability the "temporary" limit would be made "permanent". Concluding Comments Three of the voting members of our committee are transportation engineers/traffic and I again emphasize that the committee voted unanimously to recommend the 65 MPH speed limit. My personal opinion is the work place safety issue for our emergency responders by itself would justify the proposal Also, in my personal opinion,, other safety concerns would by themselves justify the proposal. Lowering the speed limit will not be a panacea. It will not make I-90 safe. However, it will make it safer. There still will be crashes although perhaps not quite as many (at least relative to the traffic volumes) There still will be injuries and unfortunately perhaps even fatalities. However, there should be a statistically significant decrease in incapacitating injuries and fatalities (at least relative to traffic volumes). In short, we should not have over-expectations but we will achieve positive results and that is exceedingly important. Please request the State to set the I-90 speed limit in the Bozeman area to 65 MPH for both passenger vehicles and trucks. Ralph W. Zimmer, Ph.D., P.E. (inactive) Chairperson, Bozeman (Area) Pedestrian and Traffic Safety Committee cc: Andrea Surratt Craig Woolard Rick Hixson Steve Crawford Rich McLane Josh Waldo Robin Crough Danielle Scharf (PTS Vice Chairperson) Mandee Arnold (PTS Secretary) Virus-free. www.avast.com