Feasibility Study

The calculations  presented in the table below demonstrate that it is technically possible and financially reasonable to proactively synchronize TA patron accounts and OTRBs with wireless validators.

Transit System ScaleSmall *)Medium **)Large ***)
Number of patrons (mill.)0.171.821
Max number of vehicles with validators en route1,1252,2007,500
Annual revenue (mill $/year)70100012,000
Annual revenue collection cost (mill $/year)8.51201440
Average number of taps/sec in peak period425406,800
Wireless Validator OTRB List length (Mbytes)454705500
Peak data download speed (Mbit/sec)0.0070.122.0
Annual cellular data cost (mill $/year)0.00250.0542.1
For comparison, cellular data cost as share of revenue collection cost

*) e.g.  Calgary, Canada

**) e.g. TTC, Toronto, Canada

***) Transport for London, UK

With a cellular plan for 120 Gbytes per month costing around $100/month or less, and with wireless download speed of several megabits per sec, synchronizing Wireless Validator data with the TA computer host does not seem to be an issue, even during the peak periods. The patrons move slow between transfers, and synchronization lag of several minutes can be acceptable.

We have developed a comprehensive model that allows to calculate the required cellular data traffic parameters, costs, and validator memory capacity for any TA configuration.