Radio modems in Intelligent Transportation Systems (ITS)

Radio modems offer reliable long range real-time data transfer. They can be used in the different kinds of wireless data transfer in mass transit systems:

Traffic light priority for public transport

Radio modems are used in systems that automatically give buses or trams priority in traffic lights. When a bus approaches a traffic light guided intersection, the on-board equipment of the bus sends a message over the data radio network to the traffic lights, which then turn on the green light signal. In this way, the time buses spend in traffic lights can be reduced by as much as 40% ¹ and total trip duration by 5%². In addition to shortening wait and travel times, the mass transit fleet can be used more efficiently. The payback time for a transit signal priority system of the Chicago Transit Authority was calculated to be less than two years because of improved operating efficiency.³ Fuel consumption and emissions can also be lowered and passenger comfort improved as unnecessary stopping and accelerating can be avoided and punctuality improved. 

Real-time passenger information systems

A passenger, who is at a bus or light railway stop, is foremost interested in knowing when the next bus or train will arrive. The perception of how long the wait time is depends on whether the time is known beforehand or not. If the traveler does not know how long the wait time will be, the time is perceived as much longer. The wait time is perceived as much shorter if the time is known beforehand e.g. shown on a real-time display, provided that the information is accurate and reliable.⁴

By providing passenger information displays, customer satisfaction is improved. In surveys 80% of passengers have evaluated intelligent transportation systems as useful.⁵ Research has also shown that 20% of  bus passengers say they have traveled by public transport more often because of on-stop displays. Actual bus passenger volumes have increased by 10-12% after installing digital countdown signs.¹

In addition to providing pre-trip information by web or mobile phone services and on-trip information by bus stop displays passengers can also be offered managed transfer availability (MTA). With MTA, passengers can be offered real-time information about available transfers at next stops already when traveling on the feeder line. Transfer protection can then be provided by ordering the receiver vehicles to wait for the incoming feeder vehicles. 

Statistics and Automatic Vehicle Location (AVL)

Obtaining statistics is vital for planning and optimizing mass transit networks, routes and schedules. Important information to collect is:

• Timetable adherence and punctuality
• Ridership/traveler information
• Variances in run times and headways
• Seasonal differences and deviations due to accidents or mass events

 With Computer Aided Dispatch (CAD), transport management centers can e.g. coordinate reserve equipment and personnel efficiently depending on actual real-time needs.

References

1. Benefits of Pilot Implementation of Public Transport Signal Priorities and Real-Time Passenger Information

2. Comprehensive Evaluation on Transit Signal Priority System Impacts Using Field Observed Traffic Data

3. Assessment of the Applicability of Cooperative Vehicle-Highway Automation Systems to Bus Transit and Intermodal Freight: Case Study Feasibility Analyses in the Metropolitan Chicago Region

4. Passenger Wait Time Perceptions at Bus Stops: Empirical Results and Impact on Evaluating Real-Time Bus Arrival Information

5. Evaluation of Acadia National Park ITS Field Operational Test