Synthesis of Safety for Traffic Operations - Transports Canada
Synthesis of Safety for Traffic Operations - Transports Canada
Synthesis of Safety for Traffic Operations - Transports Canada
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<strong>Synthesis</strong> <strong>of</strong> <strong>Safety</strong> <strong>for</strong> <strong>Traffic</strong> <strong>Operations</strong> March 2003<br />
The arrows were placed several hundred feet upstream <strong>of</strong> the driveway. Three <strong>of</strong> the<br />
sites were unsignalized, midblock driveways; one site was a signalized driveway. All <strong>of</strong><br />
the sites were in an urban or suburban setting and located along multilane arterial roads<br />
with posted speed limits <strong>of</strong> 30 to 45 mph. In<strong>for</strong>mation on site selection criteria is not<br />
provided. The study methodology is a naïve be<strong>for</strong>e-after study <strong>of</strong> right-turn conflict<br />
rates. The results are shown in Table 5.9.<br />
Site<br />
TABLE 5.9: <strong>Safety</strong> Impacts <strong>of</strong> Pavement Marking Arrows<br />
Speed Distance from<br />
Conflicts/ 100<br />
<strong>Traffic</strong><br />
Limit Conflict area to<br />
potential conflicts<br />
Control<br />
(mph) Arrow<br />
Be<strong>for</strong>e After<br />
CMF +<br />
1 45 250, 475* Unsignalized 4.7 2.4 0.98<br />
2 30 210 Unsignalized 18.6 9.2 0.91<br />
3 30 145 Unsignalized 7.7 6.3 0.99<br />
4 35 300 Signal 4.8 10.4 1.06<br />
* - two arrows were used because <strong>of</strong> the higher speed limit<br />
+<br />
- assumes that conflicts and crashes are linearly related<br />
The pavement markings at the unsignalized locations have a combined CMF <strong>of</strong> 0.96<br />
(assuming conflicts and crashes are linearly related).<br />
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