• Wed October 13 2010
  • Posted Oct 14, 2010
Des Moines, IA Blog post by Jason Pulliam [bikeiowa note: This is NOT final yet as the City Council must approve, but good news none the less!] Recent changes to the traffic lanes on Ingersoll Avenue should become permanent, city traffic engineers this week reported to City Council members. In early May, Ingersoll was �re-striped� between Polk Boulevard and Martin Luther King Jr. Parkway, decreasing the number of vehicle lanes from four to three. There is one lane in each direction, a center left-turn lane and bicycle lanes on both sides of the street. Copied below is the text of an email sent to council members that includes an assessment from City Traffic Engineer Gary Fox: The Traffic and Transportation Division has made a detailed study of the operation of Ingersoll Avenue following the conversion to a 3-lane roadway with bike lanes on May 1, 2010. This study analyzed the traffic conditions that had been listed as warranting changing Ingersoll back to the previous 4-lane configuration, and also analyzed extensive before-and-after public opinion survey results. As shown in the above analysis, traffic conditions in the Ingersoll Corridor have been generally as anticipated following the implementation of the restriping project. There has been some increase in congestion and delay, although the actual increases are much less than the perceived increases. Overall travel times during the morning and noon peak periods showed negligible changes, while the greatest increase in travel time occurred in the afternoon peak period, but was only approximately 20 seconds higher for westbound traffic traveling from ML King to 42nd Street. So congestion and delays were not higher than expected. The overall daily traffic volumes on Ingersoll are steady to a slight increase. Some reduction in traffic volumes has occurred during the morning and evening peak periods, but this has been offset by additional traffic during the remainder of the day, including the noon-time period. In addition, traffic volumes on Grand Avenue did not show an increase. These traffic counts show that there has not been a substantial diversion of traffic from Ingersoll to Grand or other parallel streets. The crash history shows a reduction of over 50% of crashes compared to the previous three-year average for the same months, and also over 50% reduction in the number of injuries reported for the after period. There have been no reported crashes involving pedestrians, bicycles or buses during the trial period. Traffic and Transportation Division staff have monitored traffic flows and conditions on a regular basis, including trips through the corridor by both vehicle and bicycle, as well as using traffic observation cameras. No major traffic problems have been observed during the study period. In addition, staff has not received reports from businesses or residents along the corridor, from motorists or bicyclists using the corridor, or from the general public, indicating any major problems. Based on the before and after public opinion surveys, the overall perception of the new configuration has changed to be substantially more favorable in the after survey compared to the before survey. Overall, 56.4% of the responses in the after survey are in favor of keeping the 3-lane configuration with the bike lanes, with 46.3% definitely and 10.1% probably. There is still significant opposition to the changes, with 42.7% in favor of changing Ingersoll back to four lanes, with 35.5% definitely and 7.2% probably. In addition, a majority of responses (52.4%) believe that the change has made Ingersoll safer, and those who responded that they had biked on Ingersoll had the highest safety rating, with 86.3% stating that they think Ingersoll is now safer with the three lanes for traffic and separate bike lanes. Based on the analysis of traffic conditions, safety and public opinion as detailed in this study, staff strongly recommends that the City Council approve the new 3-lane configuration with bike lanes as the safest and most appropriate traffic control for Ingersoll Avenue from ML King, Jr. Parkway to Polk Boulevard.

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