Civil Engineering Reference
In-Depth Information
Fig. 9.3 The extra
“
buffer
”
time needed when planning important trips. Source Reference [
5
],
p B-53. Exhibit B-33
For example, if the average travel time in the peak hour takes 30 min, a BTI of
1.20 means that a traveler should allow for an extra 20 % travel time, or 6 min, in
order to arrive at the destination on time for 95 % of the trips.
The BTI tends to be larger during peak periods than in off-peak periods: Fig.
9.3
([
5
], TTI Mobility Report, 2011, Exhibit B-33),
An example of peak hour travel time distribution is provided in Fig.
9.4
for a
section of I-75, northbound, in Atlanta.
This example shows that peak hour travel times range from 6
32 min, with an
average of 12.2 min. If a commuter wanted to arrive to work on time 95 % of the
time, he or she would have to allow 18.54 min to the trip (e.g., the 95th percentile).
-
Fig. 9.4 Distribution of peak hour travel time, atlanta, I-75 NB, I-285 to SR 120 (2007). Source
Reference [
3
], p 55. Figure 4.4
