Loading...
HomeMy WebLinkAbout1997-11-10 City Council (15)City of Palo Alto City Manager’s Report TO:HONORABLE CITY COUNCIL FROM: DATE: SUBJECT: CITY MANAGER November 10, 1997 LYTTON AVENUE DEPARTMENT: PLANNING- CMR:459:97 NEIGHBORHOOD TRAFFIC MANAGEMENT PLAN--FOLLOW-UP EVALUATION This is an information report, and no Council action is required. BACKGROUND The six-month trial installation of the Lytton Avenue Neighborhood Traffic Management Plan ended in November 1996. In January 1997, Council approved the permanent installation of the plan, with the exception of the median on Chaucer Street at Palo Alto Avenue. Staff removed the median at the end of January 1997. Attachment 1 illustrates the approved permanent (final) traffic management plan. In its approval of the plan, Council requested a follow-up evaluation of traffic counts in the neighborhood six months after removal of the median, as well as a re-evaluation of the traffic situation on University Avenue regarding the restriping of the westbound approach of University at Middlefield Road (one of the approved elements of the plan). DISCUSSION Traffic Volumes. Traffic volumes were remeasured three to five months after removal of the median. The three measurement periods discussed in this report will be referred to as the "pre-trial," "post-trial," and "final plan" measurements, conducted ~ October 1995, November 1996, and April-July 1997, respectively. Note that the Chaucer median was in place only for the post-trial measurements in November 1996. Attachment 2 compares traffic volumes for these three time periods. Volumes tend to fluctuate randomly on a daily basis by about 10 percent; thus, final plan volume measurements that have not changed by more than 10 percent with regard to previous measurements should not be regarded as having changed conclusively. Some selected observations can be made about the final plan traffic volumes compared to the pre-trial and post-trial volumes: CMR:459:97 Page 1 of 4 The volume on Chaucer has returned to its pre-trial level at the bridge, but increased and has remained higher than its pre-trial level south of Palo Alto and University.Avenues. The volumes on .th’e Palo Alto Avenue/Lytton Avenue route between Chaucer and Middlefield have increased since removal of the Chaucer median, but remain lower than their preZtrial levels. The volumes on Guinda and Fulton Streets have decreased compared to both pre-trial and post-trial levels. The final plan has reduced traffic volumes on most Lytton Neighborhood streets on the order of 15 to 35 percent (from about 100 to 800 vehicles per day, depending on the street and block), compared to pre-trial levels. The reduction is more than staff had expected afterremoving the Chaucer median: Volumes have increased on University and Hamilton Avenues compared to pre-trial levels; thus, it is probable that the traffic redirected from the Lytton Neighborhood streets (presumably "shortcutting" traffic) has moved to University and Hamilton Avenues. ¯ Comparing pre-trial and final plan measurements, the magnitudes of the volume increases on University and Hamilton are greater than the volume decreases in the Lytton Neighborhood. This suggests that the ’increases on University and Hamilton are due primarily to other factors occurring in the same time peri.’od as the Lytton Neighborhood trial, and that there is a spill-over effect from University to Hamilton. 8$th Percentile Speeds. Speeds were remeasured in mid-July 1997, five months after removal of the median. Attachment 3 compares speeds for the three time periods. Speed measurements may fluctuate by plus or minus 3 miles per hour (mph) at any given location. Thus, changes in speed of 3 mph or less should not be regarded as indicating a conclusive change. Attachment 3 shows that speeds have remained essentially unchanged compared to post-trial measurements at all locations except one. In the block of Chaucer South of Palo Alto Avenue (where the median was removed) speeds have decreased, which is desirable. Final plan speeds in all locations where traffic calming devices have been installed (and on Chaucer .south of Palo Alto Avenue, where the median was removed)’ are approximately 4 to 7 mph lower than pre-trial speeds. Restriping of University Avenue at Middlefield Road. Attachment 1 describes the restfiping of University Avenue in the vicinity of Middlefield Road. Council approved this improvement as part of the Citywide Land Use and Transportation Study. Staff recently obsevced morning traffic flow westbound on University Avenue at Middlefield Road (the CMR:459:97 Page 2 of 4 commute direction) between 8:00 a.m. and 9:00 a.m. The additional westbound lane between Middlefield and Fulton has reduced the queuing of Westbound traffic substantially, to the point that queues due to the Middlefield signal now rarely extend beyond Fulton. Some queuing still occurs on University farther east, but this is due to the signals at Guinda and other intersections, not Middlefield. The Guinda signal provides frequent gaps in westbound traffc so that residents living on university between Guinda and Fulton can exit their driveways in the morning into generally free-flowing,but not speeding, traffic. The incremental added queuing capacity (and thus delay reduction) created by this additional lane improves traffic flow somewhat at this intersection, thus offsetting, to some degree, the redirection 0ftraffc from the Lytton Neighborhood. There have been no complaints or operational problems-regarding afternoon eastbound University Avenue traffic flow, which has now been constrained to one lane at Middle field. Conclusion. The f’mal Lytton Neighborhood plan is accomplishing its purpose of redirecting some shortcutting traffic off of local ne!ghborhood streets, and reducing the speed of all traffic on those streets, even without the presence of the Chaucer median. As expected, the amount of redirected traffic is less since the removal of the Chaucer median. It is likely that some of this redirected traffic is now using Hamilton Avenue instead of University Avenue (or that some increment of existing University Avenue traffic has moved over to Hamilton Avenue), which seems inevitable due to the heavy traffic flow on University Avenue. The added second westbound lane on University Avenue at Middlefield Road helps offset this redirected traffic .by incrementally improving traffic flow at this_ location.-As previously reported to Council, the replacement of the traffic circle and raised median with permanent designs is expected to be accomplished through the FY 1998-99 CIP process. FISCAL IMPACT As previously reported to Council, the replacement of the traffic circle and raised median with permanent designs will be pursued through the FY 1998-99 CIP process. The fiscal impact of the permanent designs will be identified at that time. ENVIRONMENTAL REVIEW An Environmental Assessment (95-EIA-5) was approved by the Council in its meeting of May 8, 1994. The monitoring measurements reported herein for the final plan fall within the range included in that EIA. CMR:459:97 Page 3 of 4 Prepared By: Carl Stoffel, Transportation Engineer Department Head Review: City Manager Approval: KENNETH R. SCHREIBER Director of Planning and Community Environment EMILY HARRISON Assistant City Manager Lytton Neighborhood Study Working Group Members Crescent Park Neighborhood Association City of Menlo Park City of East Palo Alto East Palo Alto Transportation Task Force Safe Open Streets CMR:459:97 Page 4 of 4 H"I ATTACHMENT 1 ATTACHMENT 2 fill ATTACHMENT 3