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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 />

TABLE 12.3: CMFs <strong>for</strong> <strong>Traffic</strong> Signs<br />

Researcher Treatment Study Methodology No. Sites CMF Comments<br />

Be<strong>for</strong>e-after study<br />

Area-wide traffic sign<br />

Lyles et al (1986)<br />

with control group -- 1.04<br />

upgrades<br />

using crash frequency<br />

Tople (1998)<br />

TRL (2000)<br />

Arnott (1985)<br />

Tribbett et al (2000)<br />

Lalani (1991)<br />

Land Transport<br />

<strong>Safety</strong> Authority <strong>of</strong><br />

New Zealand (1996)<br />

Helliar-Symon and<br />

Ray (1986)<br />

Kostyniuk and<br />

Cleveland (1986)<br />

Improved traffic signing<br />

<strong>Traffic</strong> signing<br />

Activated Curve Speed<br />

Warning Signs<br />

Dynamic Curve<br />

Warning Sign<br />

New chevron signs<br />

Chevron signs<br />

Active warning signs <strong>for</strong><br />

following too close<br />

“Limited Sight<br />

Distance” sign<br />

Naïve be<strong>for</strong>e-after<br />

study using crash<br />

frequency<br />

Naïve be<strong>for</strong>e-after<br />

study using crash<br />

frequency<br />

Naïve be<strong>for</strong>e-after<br />

study using crash<br />

frequency<br />

Naïve be<strong>for</strong>e-after<br />

study <strong>of</strong> crash<br />

frequency<br />

Naïve be<strong>for</strong>e-after<br />

study using crash<br />

frequency<br />

Be<strong>for</strong>e-after study<br />

with some<br />

adjustments <strong>for</strong> crash<br />

trends<br />

Be<strong>for</strong>e-after study<br />

with a control group<br />

Be<strong>for</strong>e-after study<br />

with a control group<br />

6<br />

222 (Urban)<br />

136 (Rural)<br />

0.95<br />

0.85<br />

0.68<br />

0.59<br />

5 0.29<br />

5<br />

1.25<br />

0.89<br />

1.02<br />

3 0.29<br />

103<br />

3<br />

9 paired<br />

sites<br />

0.52<br />

0.46<br />

3.31<br />

1.32<br />

1.09<br />

All crashes<br />

EPDO crashes<br />

No details the<br />

signing upgrades<br />

Short after periods<br />

and no accounting<br />

<strong>for</strong> confounders<br />

Casualty crashes<br />

PDO crashes<br />

All crashes<br />

Rural areas<br />

Urban areas<br />

Close following<br />

crashes<br />

All crashes<br />

Page 160

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