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Fixed Route Transit Scheduling. Alexis Matrka Lauren Park Lan Wu. Two Different Approaches. 1. Level of Service Policy Orientation Provide basic service level I.e. train every 10 minutes for off-peak, and 5 minutes for peak Generally used to provide minimum service.
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Fixed Route Transit Scheduling Alexis Matrka Lauren Park Lan Wu
Two Different Approaches • 1. Level of Service Policy Orientation • Provide basic service level • I.e. train every 10 minutes for off-peak, and 5 minutes for peak • Generally used to provide minimum service
Two Different Approaches • 2) Demand Orientation • Look at current demand and provide enough seats that meet that demand • Where demand doesn’t exist, don’t provide it • I.e. 2am-5am
Different Viewpoints • 1) Management viewpoint • Minimize total cost • Costs: vehicle hours and miles • Travel varies by time of day, day of week, and time of year • In order to meet demand at peak times, excessive service may be necessary
Different Viewpoints • 1) Management viewpoint, cont • May be in best interest to discourage peak ridership • Not worth it to add vehicles and drivers for that short time • Possible disincentive: lower prices for off-peak times • Not worth it unless a total piece of work is eliminated
Different Viewpoints • 2) Driver Viewpoint • Want schedules that easy to meet, convenient layovers, short work days, and convenient starting times. • Need breaks and mealtimes during the day
Different Viewpoints • 2) Driver Viewpoint, cont • Labor contracts with drivers usually specify constraints • i.e. drivers working >10 hours/day need to be paid extra • Contract provision have a major effects on schedules, costs, spread penalties, layover provisions, split shifts, etc
Different Viewpoints • 3) Customer Viewpoint • Need to be at destination at given time, want to avoid waiting, want reliable service, schedules that are easy to remember, availability of service at all hours, weekends, holidays
Application: Bob’s Job • Bob works in New York City at the School of the Future, near the 23rd and Park 6 train stop. • To save money, he lives in the Bronx. His closest subway station is the 1 train Van Cortlandt Park at 242nd and Broadway. • To maximize his utility, Bob would like to take at most 50 minutes to get to work.
Application, Cont • To get to work, Bob must start at Van Cortlandt, ride the 1 train to 42nd street, take the shuttle to Grand Central, then take the 6 train to 23rd. • We researched the headways for all three trains, and the transit times for these three rides.
Application, Cont • Flow shop application • Bob going to work is one job • Each platform and train is a machine • The processing times on each machine are sometimes stochastic and sometimes fixed • There is a fixed order • No machine can start without the prior completing
Application, Cont • 1 train at 242nd: expect to wait 0-7 mins • Ride to 42nd: expect to take 38-39 mins • Shuttle at 42nd: expect to wait 0-3 mins • Ride to Grand Central: expect to take 2 mins • 6 train at Grand Central: expect to wait 0-5 mins • Ride to 23rd: expect to take 4 mins
Application, Cont • We ran 100 trials by generating random numbers within the stochastic ranges • Compiled total transit times • Average: 52 minutes • Shortest transit: 45 minutes • Largest transit: 60 minutes
Application, Cont • Is it worth it to add more trains in order to lower this 52 minute expected travel time to 50 minutes? • Only reduce waiting times at 242nd and GCT • Number of trains would need be increased • Congestion • Monetary concern • Ran this simulation of decreasing headways to 5 minutes and 242nd, decreased total transit by less than 2 minutes
Application, Cont • Conclusion • Not worth money • Congestion may cause transit time to increase even more