Road Safety Performance Associated with Improved Traffic Signal Design and Increased Signal Conspicuity

6.0 Data for Road Safety Evaluation

Traffic and safety data was collected at 25 locations where improvements to the traffic signals were made. Considerable effort was undertaken to collect reliable traffic volume data for the before and after time periods. Initially, collision data was investigated for use in the road safety analysis. However, the quality and quantity of the police-reported collision data in British Columbia has deteriorated in recent years, making the collision data somewhat unreliable. In addition, the time lag between the time of the collision event and when the data is available from the collision database is lengthy and as such, the data was not useful for this safety analysis. Fortunately in BC, the public nature of the Insurance Corporation of BC (ICBC) provides another complete source of safety data. ICBC warehouses the provincial auto insurance claims data that has been proven to be very useful in road safety analysis (de Leur and Sayed 2001). This auto insurance claims data is very current, comprehensive and considered quite reliable for intersection locations. As such, the before and after claims data was obtained and used in the time series safety analysis. Finally, the date of the signal improvements was obtained and verified such that accurate before and after time periods could be established.

It is noted that similar data (traffic volume data and claims data) was collected for a group of comparison sites. This group of comparison sites is used to improve the reliability of the time-series safety analysis as described in the subsequent section. A summary of the treatment sites is provided in Table 2.

Table 2: Description of Improvement Sites

ID No.	Site Type	Major Road	Minor Road	City Location	Implementation Date
1	Treatment	Rte 17	Halibuton	Saanich	November 2000
2	Treatment	Rte 17	Island View	Saanich	November 2000
3	Treatment	Rte 17	Beacon	Saanich	November 2000
4	Treatment	Rte 1	Morden	Nanaimo	April 2001
5	Treatment	Rte 1	Cedar Rd N.	Nanaimo	April 2001
6	Treatment	Rte 19	College Rd	Nanaimo	April 2001
7	Treatment	Rte 19	Jingle Pt	Nanaimo	April 2001
8	Treatment	Rte 19	Northfield	Nanaimo	April 2001
9	Treatment	Rte 19	Molstar/Jingle	Nanaimo	April 2001
10	Treatment	Rte 19	Aulds	Nanaimo	April 2001
11	Treatment	Rte 19	Ware	Nanaimo	April 2001
12	Treatment	Rte 19	Cook Creek	Qualicum	April 2001
13	Treatment	Rte 19	Cliff	Courtney	June 2001
14	Treatment	Rte 19	Comox	Courtney	June 2001
15	Treatment	Rte 19	Ryan	Courtney	June 2001
16	Treatment	Rte 19	26th St	Courtney	June 2001
17	Treatment	Rte 97	Rt 33	Kelowna	October 2000
18	Treatment	Rte 97	Prairie Valley	Summerland	October 2000
19	Treatment	Rte 97	Rosedale	Summerland	October 2000
20	Treatment	Rte 97	Banks	Kelowna	October 2000
21	Treatment	Rte 97A	Smith	Armstrong	October 2000
22	Treatment	Rte 97A	Cliffe	Enderby	October 2000
23	Treatment	Rte 16	1st Ave	Prince George	June 2001
24	Treatment	Rte 17	17th Ave	Prince George	June 2001
25	Treatment	Rte 18	20th Ave	Prince George	June 2001

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