Loading...
2022-067 Citywide Speed Study Follow UpOctober 14, 2022 Report No. 2022-067 INFORMAL STAFF REPORT TO MAYOR AND CITY COUNCIL SUBJECT: Follow-up on Council Work Session regarding the 2022 Citywide Speed Study BACKGROUND: On September 27, staff presented the Citywide Speed Study to Council as a work session item. A follow-up work session on residential speed limits is scheduled for the October 18 Council meeting. To maximize time for the discussion of this topic, staff prepared this report to provide follow-up information to Council in response to items discussed at the September 27 work session. Staff also followed up with TxDOT and confirmed a three- to six-month timeframe for their review of the Citywide Speed Study is expected. DISCUSSION: Staff offer the following responses and additional information regarding discussion on the Citywide Speed Study during the September 27 work session: • Council Member Davis sought clarification on how certain roads, collector streets like Hinkle Street or Malone Street, were not included in the Citywide Speed Study. Staff responded that on these streets, the default prima facie speed limit of 30 MPH has generally been applied, in most cases based on character of the street (i.e. number of lanes, adjacent development). Streets of this character would generally be studied under one of the following circumstances: 1) the speed, based on design of the street, is inappropriately low, and study to establish an appropriate increase in the speed limit is necessary, or 2) crash trends demonstrate poor safety performance on the street, and study to determine if a speed limit reduction is warranted, or if street alterations may potentially reduce crash trends. The Citywide Speed Study offers an abundance of data to assist staff in identifying additional streets for study in the future. • Mayor Pro Tem Beck asked if the results of the Citywide Speed Study data would be available publicly. Staff are currently working with Tech Services to format the GIS data used to generate the study so it can be hosted in a publicly available interactive format. • Mayor Pro Tem Beck asked if the evaluation under this study could shed light on the influence of speed limit changes previously adopted by the City, and the influence of that change on safety. Because the purpose of this study was specific to assessing appropriate speeds, based on observation of current traffic operations and recent safety trends, this question was not specifically considered. An important acknowledgement of the study to emphasize is that speed is one factor in safety performance of a street over time, so in addition to lowering speeds where crash rates are high, additional changes to reduce crash potential, or severity of crashes that occur, are necessary responses to advance the City’s Vision Zero commitment. This requires partnership with TxDOT, as many of these streets are not under City control. Attention must also be directed to where data evidences October 14, 2022 Report No. 2022-067 potential for future severe or fatal crashes to occur, which supports funding requests through the Highway Safety Improvement Program (HSIP), or other grant funding opportunities that are available to improve roadway safety. • Council Member Maguire sought clarification regarding the need to comply with requirements established by law, or outlined by engineering guidance and TxDOT policy, which fundamentally are to post the speed limit within 5 MPH of the observed 85th percentile speed, except where high crash rates allow for more significant reductions. It is staff’s opinion that adherence with the law, policy and engineering guidance is necessary for the speed limits to be effective and enforceable. The City does have the opportunity to modify a street to calm traffic and conduct a follow-up study to alter the speed limit, but this approach would ideally be targeted to streets with demonstrated crash trends to address patterns of fatal or severe injury crashes. • Council Member Watts asked where the crash data in the study was derived, and over what period. This data reported covers the 2019 – 2021 timeframe, and was assembled using TxDOT’s crash reporting information system, or C.R.I.S. This is a public database of crash data reported by multiple agencies, including Denton PD, the University PD’s, Texas DPS. The public data query tool is available using the following link, and fields included in the analysis are highlighted in the Study: https://cris.dot.state.tx.us/public/Query/app/home • Council Member Watts sought clarification of how fatalities and serious injury crashes influenced the recommendations of the study. Staff generally followed TxDOT guidance outlined in the response to Council Member Maguire’s question above, and where trends of severe injury or fatal crashes suggested a more aggressive recommendation may be appropriate, these additional factors were applied to further support the recommendation to reduce the speed limit. • Council Member Watts asked if travel time had any influence on recommendations to lower speed limits. Staff shared that anecdotally a reduction in speed limit often has minimal impact on corridor travel times, particularly when the change in speed limit is minimal, like the 5 MPH reductions recommended by this study. Traffic engineers do often model corridor level changes to streets, typically when evaluating design alternatives, or to optimize traffic flows along a corridor with multiple signalized intersections. • Council Member Davis asked about adjusting speed limits on a road that will, in the future, be altered significantly, the example being increasing the speed limit on Bonnie Brae Street between Ft. Worth Drive and Vintage Boulevard, which will be reconstructed in the future. In the case of this specific street, the urban district prima facie speed of 30 MPH was applied, despite the rural character of the road and its surrounding environment, so maintaining the current posted speed limit would not be considered enforceable. Most streets included in the study are located within the designated urbanized area of the City, so this specific street is an outlier in that regard, and as development occurs and the road is improved, it will become an urban street where a reduced speed limit would be considered appropriate. October 14, 2022 Report No. 2022-067 • Mayor Hudspeth asked how extenuating circumstances in crash data would be considered, such as driving under the influence (DUI), distraction, etc... From an engineering perspective, these factors are generally not considered in an evaluation, based on the immense amount of data being analyzed, the potential for inconsistent data entry, and underreporting of factors such as distraction. These factors may be considered in a more detailed analysis of an intersection, or a specific corridor, but from a speed setting policy the objective is to understand the crash data consistently, as a whole, without introducing subjectivity that would influence results of the analysis. • Mayor Hudspeth asked how a street like Mayhill was considered in the study, with the upcoming construction of a bridge over the DCTA rail line that will significantly alter travel patterns in the surrounding area. Given the significant scope of the Mayhill project, and other streets like Bonnie Brae, some portions of these roads adjacent to upcoming projects were included in the study, particularly where the influence of construction activity, or where recent development like the opening of new Denton High School would warrant the review of speeds and potential recommendations in the near-term. Similar streets that were not studied, like Hickory Creek Road, were often based on other factors, like current construction activities that would prevent collection of data to make an appropriate engineering recommendation. • Mayor Hudspeth recommended that staff provide visuals to inform the public and assist in feedback provided to the City regarding street designs. Staff are currently assessing a variety of traffic calming elements, ranging from driver feedback signs and temporary curb extensions using flexible bollards. As the effectiveness of these approaches are determined from engineering evaluation, additional details will be prepared to share with the public. STAFF CONTACTS: Brett Bourgeois, PE, Deputy City Engineer Brett.Bourgeois@cityofdenton.com Nathan George, AICP, Senior Planner: Bicycle, Pedestrian and ADA Coordination Nathaniel.George@cityofdenton.com