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Travel Time And Alternate Route On CMS. Chao Chen, Karl Petty PeMS Development Group University of California, Berkeley 10/24/2002. Provide real-time information where it’s most helpful. Travel times Alternate routes Incidents Updated automatically. Benefits.
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Travel Time And Alternate Route On CMS Chao Chen, Karl Petty PeMS Development Group University of California, Berkeley 10/24/2002
Provide real-time information where it’s most helpful • Travel times • Alternate routes • Incidents • Updated automatically
Benefits • Minimize travel time by picking the best route • Reduce uncertainty in travel time • Distribute load to less congested corridors • Quantify delays
Feasibility • There are many CMS on CA freeways • PeMS already measures and predicts travel times • The information is easily made available • A similar CMS travel time service exists in Paris and works well District 12 CMS locations
Objective of this study • Quantify benefit of travel time on CMS • Choose locations where potential benefits are greatest • Alternate routes are available • Lots of congestion
Travel time variability • Travel times for 20 days in October, 2000, on I-10E, between pm 1.3 and 48.5, starting every 5-min, between 5 am and 8 pm • Shows large variation between 42 and 130 minutes • Permits prediction of travel time
Congestion occurs on both routes Travel time varies between 15 and 45 minutes Travel times on two routes in San Diego • Average travel times are similar – these are equally good alternatives
Prediction minimizes travel time • Each dot represents one trip • Prediction almost always picks the best route • Even when prediction doesn’t pick the best route, the travel difference is small
2-minute reduction for 23 minute trip, about 9%, during peak hour Predictoin achieves close to minimum travel time Average travel time reduction
Prediction reduces uncertainty • Prediction is accurate to 2 minutes on 23 minute trip • More than 50% reduction in uncertainty in peak hours
List of study areas • District 7 – Los Angeles and Ventura Counties, from I-10 and I-210 to downtown • District 11 – San Diego, from I-5 and I-805 to downtown (I-5 and I-163) • District 11 – from SR-125 and I-8 to downtown • District 12 – Orange County, from I-5 and I-405 to I-5 and SR-91 • District 12 – from I-5 and I-405 to I-405 and I-605
Still to do • Do same study for more O-D locations • Decide how to interface PeMS and Caltrans CMS system • Make sure PeMS travel times are accurate
Conclusion • Travel time prediction on CMS can reduce travel time when alternate routes exist • It greatly improves travel time predictability