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162 I N N O VAT I O N S I N T R AV E L D E M A N D M O D E L I N G , V O L U M E 2 is determined both by the duration of the activities and in-motion. Data are collected using manual, portable by the travel times to and from them. See Vovsha and (road tube), and permanent automatic traffic recorders Bradley (1). and intelligent transportation systems methods. Traffic count data are published by hour and vehicle type by functional class on a statewide basis (12). STATUS OF THE TIME-OF-DAY Table 1 shows the percent of half tours (departures MODEL VALIDATION and arrivals) and trips from the model and the percent of passenger vehicle traffic by hour of day for the base year In the development of the MORPC TOD model, a dis- 2000. As noted earlier, the model schedules tours aggregate validation was achieved using the Home Inter- between 5:00 a.m. and 11:00 p.m. Therefore, those view Survey (HIS) data records. The MORPC validation hours account for traffic between midnight and 5:00 report shows the results for the TOD model versus the a.m., and are not directly comparable with the traffic observed values from the HIS, which, as expected, count data. The traffic data by functional class are accu- match. The TOD model, however, has not yet been fully mulated on a statewide basis; as such, the summary validated against external data. MORPC does not have tables may not be as representative as data solely from a sufficient number of traffic counts by peak hour or the Columbus region. To calculate the average, the share peak period to validate either the hour-grained TOD by functional class was weighted by vehicle-miles- model or the period-level traffic assignments. To date, traveled share, as reported in the Highway Performance only the 24-h traffic and transit assignments have been Monitoring System. validated (with respect to counts) and used for official Although number of tours or trips cannot be com- planning purposes. The hour-level detail in the MORPC pared directly with traffic counts, several observations microsimulation results is aggregated to four general can be garnered. As seen from Table 1, the model is time periods (3-h a.m. and p.m. peaks, midday, and showing more tours starting or concluding in the a.m. nightearly morning) for highway and transit network peak hour and period than the p.m. peak hour and loading. The hourly detail, however, is available in the period. This can be partly explained by the model simu- final simulated tour-record-level disaggregate output. lating an average weekday, as opposed to an average day. Furthermore, because both the HIS and the model show that people are more likely to make a stop on the TIME-OF-DAY COMPARISON BETWEEN THE inbound half of the tour, the trips are more balanced to TIME-OF-DAY MODEL AND TRAFFIC COUNTS the p.m. peak than the half tours. However, part of the apparent underestimation may be explained from the The Ohio Department of Transportation (ODOT) col- underreporting of nonmandatory tours in the HIS. While lects traffic monitoring data for Interstate, U.S., and state the model has been calibrated to take the underreporting routes in the state of Ohio. Traffic monitoring data into account, it is possible that some tours are still being include vehicle volume, vehicle classification, and weigh- missed. TABLE 1 Percent of Tours, Trips, and Passenger Vehicle Traffic by Hour of Day, Base Year 2000 Traffic Counts by Functional Class MORPC Model (%) Total Urban Areas Statewide (%) Hour Half Tours Trips Average 11 12 14 16 17 5 2.1 1.9 1.8 1.9 2.4 1.7 1.6 1.4 6 2.7 2.6 4.6 5.2 5.5 3.9 3.8 3.7 7 8.1 7.7 6.9 7.7 7.2 6.0 6.0 5.9 8 9.0 8.5 5.6 6.1 5.6 5.2 5.2 5.2 9 5.8 5.5 4.7 4.8 4.5 4.8 4.6 4.6 10 4.4 4.4 4.7 4.4 4.8 5.1 4.8 4.8 11 4.3 4.4 5.3 4.8 5.1 5.9 5.8 5.8 12 4.6 4.6 5.7 5.3 5.3 6.2 6.2 6.3 13 5.3 5.4 5.8 5.7 5.4 6.0 5.9 6.0 14 5.3 5.2 6.4 6.4 6.1 6.5 6.5 6.7 15 6.4 6.1 7.6 7.7 7.5 7.5 7.6 7.9 16 7.5 7.4 8.1 8.2 8.2 7.8 8.1 8.2 17 7.0 7.3 8.2 8.3 8.3 7.9 8.2 8.3 18 6.7 7.1 6.2 6.1 6.0 6.2 6.5 6.5 19 5.5 5.7 4.6 4.2 4.3 4.9 5.1 5.1 20 4.4 4.5 3.8 3.5 3.6 4.1 4.3 4.3 21 4.5 4.7 3.2 3.0 3.1 3.4 3.5 3.3 22 3.2 3.4 2.3 2.2 2.4 2.3 2.4 2.3 23 3.4 3.7 1.6 1.5 1.8 1.6 1.5 1.5 Total 100.0 100.0 97.3 97.2 97.1 97.1 97.6 97.8