California Department of Transportation

EDAPTS Smart Transit System

Why We Pursued This Research

EDAPTS Smart Transit Sign at City Hall Downtown SLO

Transit users in small urban and rural communities often face significant problems when trying to use transit as a viable mode of transportation. The uncertainty of simply catching a bus that may come only once every hour or two to a rural bus stop is one of them. It's the old "Have I missed it?"question. At the same time, the small transit system operator typically has problems just maintaining schedules and is faced with elevated safety concerns for drivers and passengers when buses are on long headway sections of a route, especially in remote areas. To build reliable service and increase ridership these problems must be dealt with efficiently and effectively.

Intelligent Transportation Systems (ITS) may offer solutions to some of these problems. However, when small urban and rural transit agency managers are asked the question, "Why don't you make more use of ITS technology to resolve operational and customer service problems?" the answer usually contains concerns over the high cost and complexity of the systems needed to implement the solution. The stigma of cost and complexity is keeping ITS from developing in these smaller markets. To investigate ways of making ITS cheaper for the small transit operator, the California Department of Transportation teamed with California Polytechnic (Cal Poly) State University at San Luis Obispo and the City of San Luis Obispo Transit (SLO Transit) on the Efficient Deployment of Advanced Public Transportation Systems (EDAPTS) Research Project.


>Shown below is the EDAPTS Smart Transit Sign video in different formats:

What We Did

The team identified unique small transit operational and customer service problem areas where ITS might help, developed conceptual solutions, and tested those solutions in a real world environment. They started with two basic ground rules:

  1. ITS solutions must be, (a) low cost, (b) easily configurable to local needs, and (c) non-proprietary
  2. System performance trade-offs can be made to significantly reduce costs if they do not adversely impact the usefulness of the deployed system

First, in discussions with transit agency managers and other stakeholders the team found that:

  • Low cost means not just low purchase price, but especially a low cost of installation, operation, and maintenance.
  • Easily adapted means expandable or contractible configurations that include only those capabilities most in need at the time of purchase. Solutions should use standard, plug-in modules and sub-assemblies to expand system performance over time.
  • Non-proprietary means that the solution is free from restrictive intellectual property rights clauses that (a) prohibit efficient interfacing with other systems, (b) restrict system modifications needed to accommodate changing agency operations needs, or (c) limit the use, operation, and maintenance of the systems throughout their life.

Next, they completed the initial research, defined the conceptual solutions, and then developed detailed solutions using the FHWA National ITS Architecture Guidelines and the National Transit Coordinated Interface Protocol's (TCIP) as integral elements of the design. The conceptual designs incorporated novel, cost saving approaches such as transmission of digital data by time sharing the current analog voice radio link, using a single text paging service to simultaneously update bus arrival data at all bus stop Dynamic Messaging Sign's (DMS), and using solar power for the signs to allow installation anywhere.

The final conceptual design incorporated the following functional elements:

  • Automatic Vehicle Location (AVL) using the Global Positioning Satellite (GPS) system.
  • Dynamic Messaging Sign for real time bus arrival information at bus stops.
  • Solar power option for the DMS to allow mounting at remote, unpowered bus stops.
  • Central dispatch software and internet web page showing current bus locations and schedule adherence data.
  • Silent emergency alarm for situations requiring police/emergency intervention.
  • RF modem for transmission of digital data over the voice radio link.
  • Mobile Data Terminal (MDT) to monitor bus data sources, calculate and display information to drivers and route relevant bus data information to the RF modem.
  • Card reader input for magnetic or electronic fare media
  • Keypad entries from the bus driver
  • Time of day using GPS time base

Finally, a field test of the design was done using equipment assembled from commercial off the shelf parts, material, and sub-systems. The hardware was coupled with non-proprietary transit management software developed by Cal Poly. Test systems were installed on the SLO Transit bus fleet and critical performance parameters were measured. Transit riders and agency personnel were surveyed to determine how effective the systems were in improving service and solving operational problems. Changes in safety, operational efficiency, employee satisfaction, and customer service level were selected as performance measures. Following completion of the research project, all field test assets were turned over to the local partners who continue to use it in the daily operation of the transit system. The local partners have enhanced the system with new functions to provide real-time bus pass verification.

What We Concluded

Focused performance vs. cost trade-offs can significantly lower the life-cycle cost of ITS ownership in the small transit environment without impacting performance. The EDAPTS project, has shown that designs taking advantage of unused operational capacity and modularity can help bring the advantages of ITS to this currently underserved market area. It has also shown that smaller agencies have an interest in this technology to help them solve day-to-day operational problems and better serve their customers, when it is affordable. Transit customers, transit operators, and transit drivers alike have embraced the unique design concepts and lower cost approaches developed in this project. Initial discussions with private industry representatives indicate that the EDAPTS designs have significant commercial product appeal.


Provide new technology transfer funding for EDAPTS concept products. Find private industry suppliers who will bring them into the ITS market as commercial products. Implementation strategies use pooled fund studies, partnerships with private industry, and associations with public/private cooperatives such as the California Center for Innovative Transportation. High-interest elements include the solar powered DMS and the "Data Over Voice Radio Link" transmission concept.

List of Contacts

For More Information About This Research Project

Bruce Chapman
Research Analyst II
California Department of Transportation
1227 O Street, 5th Floor
Sacramento, CA 95814
(916) 654-9454
Jeffrey Gerfen
Principle Research Engineer
California Polytechnic State University Foundation
ARDFA, Bldg 007
San Luis Obispo, CA
(805) 756-2990