5. PROGRAM EVALUATION (continued)

5.3.3 Speed Results

5.3.3.10 Phoenix – Coral Gables Drive North/South Segment

The north/south portion of Coral Gables Drive is wide and lined with expensive single family homes. This segment received enforcement and education as well as a Tyregrip™ installation between Waves 4 and 5. Only three waves of data (Waves 1, 4, and 5) were collected. The speed results for this segment are presented in Table 69 and Figure 17.

Table 69. Phoenix – Coral Gables Drive North/South Segment Speed Results

Wave
Measure

Mean Speed (mph)

Mean Difference From Wave 1 (mph)

Mean Above Limit (mph)

Mean of Speeders (mph)

N and % At or Under Limit

N and % < 7 mph Over

N and % 7+ mph Over

Total N

1

32.937

 

4.437

7.773

7627
28%

10807
39.6%

8837
32.4%

27,271

2

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

4*

32.513

-0.424 (.000)

4.013 (.000)

7.330 (.000)

9223
33.3%

11274
40.7%

7183
26%

27,680

5**

31.467

-1.470 (.000)

2.967 (.000)

6.545 (.000)

10603
39.6%

11374
42.5%

4776
17.9%

26,753

* After the application of education and enforcement
**After addition of Tyregrip™ material to education and enforcement


In addition to the significant drop in mean speed in each successive wave, there was a notable reduction in the number of vehicles traveling 7+ miles over the limit. This drop of over 4,000 cars is far in excess of the overall reduction in vehicles counted of only 518 between Wave 1 and Wave 5. Thus, diversion cannot possibly explain the observed results. Also, the marked effect of the addition of the Tyregrip™ material on mean and excessive speeds is noteworthy.

Figure 17. Speed Classes on Phoenix – Coral Gables North/South Segment

line chart shows comparison of speed classes
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