ITE Journal March 2018 - 35

Traffic Circle and Roundabout Sites
The percentage of drivers yielding right of way to pedestrians at
each site located at either traffic circle or roundabout locations
during the baseline, when the temporary sign was in place, and each
month after the permanent signs were in place is shown in the lower
frame of Table 2. The installation of the temporary gateway led to an
increase in the percentage of drivers yielding to pedestrians at each
site. During baseline conditions, yielding averaged 13 percent with
a range of 9 to 19 percent. When the temporary gateway treatment
was evaluated, yielding increased to 43 percent with a range of 29
percent to 54 percent. Once the permanent gateway treatments were
installed, yielding remained consistent at the one site where no sign
was damaged (Marshall Circle SE Leg) and declined at two of the
sites that lost a sign element (Marshall NW Leg and the roundabout
at East Main at 5th Street). It should be noted that the effects of
the gateway were smaller than at the midblock and intersection
locations. This is likely due to poorer sight distance at roundabout
and traffic circle sites when exiting the roundabout.

Driver Speed
Speed at the Crosswalk and Dilemma Zone
Table 3 shows the baseline speed measure, and the speed measures
obtained after the gateway was introduced in June, August, and
October. These data show that driving speeds decreased after the
gateway was installed at all 10 crosswalk locations where speed was
measured. Sites with baseline speeds below 25 mph showed the
smallest effect size. Mean speed reductions as the vehicle traversed
the crosswalk for all sites with a baseline mean speed of 25 mph
or more are shown in Table 4. These data show that the speed

reductions at these sites averaged around 4 mph and remained
consistent over the 5-month measurement period.
Table 4. Speed reductions at the crosswalk and at the dilemma zone at each site
during June, August, and October. NA for "Not Applicable" for Westnedge refers to
destruction of the signs. The NA for the other sites were removed for construction.

Location
Monroe
Stadium
Huron
Westnedge
Nixon
Division
Cherry
Mean

Speed Reduction
at Crosswalk
Jun.
Aug.
Oct.
2.7
1
1.2
3.2
1.9
2.4
4.6
9.4
8.3
6.1
NA
NA
3.6
3
3.5
8.3
7.9
NA
3.3
4.7
3.3
4.5
4.7
3.7

Speed Reduction
Dilemma Zone
Jun.
Aug.
Oct.
1.3
0
0.3
0
0
1
3.4
8.2
7.4
3.3
NA
NA
2.4
1.9
3
3
5
NA
2.8
4.1
3.5
2.3
3.2
3

These data show that drivers began to slow at the dilemma zone
and that the mean reduction in speed varied between 2 and 3 mph.
This would imply that drivers might not be expected to engage in
hard braking because they begin slowing at a reasonable distance
when approaching the gateway.

Speed Distributions
The speed distributions at the crosswalk at each site intersection and
midblock crosswalk is shown in Figure 4. It is clear that the entire
distribution of speeds at the crosswalk are shifted toward slower speeds.

Table 3. Vehicle speed at the Dilemma Zone and the Crosswalk at each site during baseline and each of the three post treatment measures.
Baseline
Jun
Aug
Oct
Mean Speed
Mean Speed
Mean Speed
Mean Speed
Dilemma Zone Crosswalk Dilemma Zone Crosswalk Dilemma Zone Crosswalk Dilemma Zone Crosswalk
SW Michigan
Westnedge & Ranney
N.Main, Three Rivers
East Main, Benton Harbor
Monroe, Allegan
Grand Rapids
Cherry & Hollister
Wealthy & Henry
Ann Arbor
Stadium at High School
Division & Jefferson
Nixon & Bluett
Huron

27.6
23.9
29.4
27.2

29
22.6
19.2
28.1

24.3
22.8
27.6
25.9

23.0
21.6
18.8
25.4

NA
21.5
27.4
27.2

NA
14.0
15.7
27.1

NA
20.5
27.2
26.9

NA
19.7
16.4
26.9

25.6
24.8

25.2
24.4

22.8
24.4

21.9
22.0

21.5
24.7

20.5
23.6

21.5
23.0

20.5
22.3

34.1
28.1
32.8
32.8

30.6
27.4
32.3
32.9

31.6
25.4
28.5
29.4

27.6
19.1
27.1
28.3

32.1
22.6
31.6
24.6

28.9
19.5
29.3
23.5

29.6
NA
29.9
23.4

28.4
NA
28.8
22.6

w w w .i t e.or g

M arc h 2 01 8

35


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Table of Contents for the Digital Edition of ITE Journal March 2018

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http://www.nxtbook.com/ygsreprints/ITE/ITE_December2019
http://www.nxtbook.com/ygsreprints/ITE/G110939_ITE_November2019
http://www.nxtbook.com/ygsreprints/ITE/G110110_ITE_October2019
http://www.nxtbook.com/ygsreprints/ITE/G110109_ITE_September2019
http://www.nxtbook.com/ygsreprints/ITE/G108559_ITE_August2019
http://www.nxtbook.com/ygsreprints/ITE/G108250_ITE_July2019
http://www.nxtbook.com/ygsreprints/ITE/G107225_ITE_June2019
http://www.nxtbook.com/ygsreprints/ITE/G104039_ITE_May2019
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http://www.nxtbook.com/ygsreprints/ITE/G104036_ITE_March2019
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http://www.nxtbook.com/ygsreprints/ITE/G100155_ITE_December2018
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