AGENDA #5f
MEMORANDUM
TO: Mayor and Town Council
FROM: W. Calvin Horton, Town Manager
SUBJECT: Follow-up Report Regarding Traffic Studies and Traffic Calming Measures on Hillsborough Street
DATE: May 9, 2005
This is a follow-up report regarding traffic studies and traffic calming measures on Hillsborough Street. Please see Attachment 1 for an area map.
At its January 26, 2004 meeting, the Town Council received and referred petitions requesting that the Town conduct traffic studies and implement traffic calming measures to reduce speeding and cut-through traffic problems on Hillsborough Street. The petitioners cited speeding as the primary concern on Hillsborough Street, compounded by the hill and curves which exist on a portion of this street.
At its April 26, 2004 meeting, the Council received a staff report (Attachment 2) including traffic calming recommendations for Hillsborough Street. The Council approved the following traffic management measures on Hillsborough Street:
We also noted that we would monitor the effectiveness of the traffic calming measures on Hillsborough Street and provide a follow-up report for the Council’s information.
DISCUSSION
Town staff implemented the following traffic management measures on Hillsborough Street as directed by the Council:
1. Review the placement and number of signs and add orange flags to speed limit signs: Town staff reviewed the existing signage on Hillsborough Street between Rosemary Street and Airport Road, and installed the following sign improvements:
· Added two new speed limit signs
2. Install a pole mounted speed detector: Town staff installed an electronic pole mounted speed detector in January 2005 on the east side of Hillsborough Street between North Street and Mill Race Drive. The speed detector monitors traffic and displays the speed of vehicles traveling northbound (downhill) on Hillsborough Street.
3. Focused and Consistent Speed Enforcement: The Police Department actively enforces speed regulations on Hillsborough Street and will continue to do so to the extent possible with available resources.
Town staff conducted traffic studies before and after installation of the electronic speed detector. The before study was conducted during the first week of November 2004 following installation of the above listed sign improvements and prior to installation of the electronic speed detector. The after study was conducted during the first week in April 2005 of this year at the same locations on Hillsborough Street after the electronic speed detector had been installed and operating for approximately three months. A comparison of data from the before and after traffic studies is provided in the following table:
Comparison of Traffic Studies on Hillsborough Street
(Before and After Installation of Electronic Speed Detector)
|
Location |
Traffic Volume |
Average Speed (mph) |
85% Speed (mph) |
|
1. Between Rosemary Street and North Street |
|
|
|
|
a) Weekday Average |
|
|
|
|
Before |
8041 |
30 |
34 |
|
After |
8680 |
32 |
37 |
|
b) Weekend Average |
|
|
|
|
Before |
5812 |
30 |
35 |
|
After |
5790 |
33 |
38 |
|
2. Between North Street and Mill Race Drive (close to North St) |
|
|
|
|
a) Weekday Average |
|
|
|
|
Before |
8234 |
35 |
40 |
|
After |
8857 |
26 |
32 |
|
b) Weekend Average |
|
|
|
|
Before |
6507 |
35 |
40 |
|
After |
6105 |
28 |
32 |
|
3. Between North Street and Mill Race Drive (close to Mill Race Dr ) |
|
|
|
|
a) Weekday Average |
|
|
|
|
Before |
7677 |
37 |
42 |
|
After |
8897 |
28 |
34 |
|
b) Weekend Average |
|
|
|
|
Before |
5938 |
42 |
47 |
|
After |
6401 |
31 |
35 |
Attachment 1 shows the locations of traffic study data collection.
Based on the traffic study results:
From field observations and review of the study data, we believe that a combination of police enforcement and installation of the electronic speed detector has generally resulted in a moderate reduction in speeding on Hillsborough Street. However, the traffic calming measures did not achieve dramatic speed reductions, and we cannot say that any one measure (sign improvements, electronic speed detector, or police enforcement) was significantly more effective than another in this case. Vehicles continue to routinely exceed the posted 25 mph speed limit, particularly when traveling northbound (downhill), suggesting that because of the steep grade of much of the road it is difficult for drivers to maintain 25 mph without braking.
As reported in the attached April 26, 2004 report, because of the steep grade and curves on much of Hillsborough Street, and numerous intersecting streets and driveways, practical locations for traffic calming devices such as speed humps are limited. Of particular concern is the difficulty in placement of advance warning signs and the provision of adequate sight distances necessary to properly prepare drivers as they approach a physical traffic control device such as a speed hump.
CONCLUSION
Physical traffic control devices such as speed humps are not suitable on Hillsborough Street because of its steep grade and curves, and numerous intersecting streets and driveways. Based on the results of traffic studies, we found that the installation of passive traffic calming measures such as the speed detector, improved signs and markings, and increased Police enforcement have resulted in modest reductions in vehicular speeding on Hillsborough Street.
We plan to relocate the speed detector from northbound to southbound before schools are back in session in the fall. We will continue to monitor speeding conditions on Hillsborough Street, and will periodically relocate the electronic speed detector so that it will continue to gain the attention of drivers on different segments of the street.