The National Academies

Transit IDEA J-04/IDEA 53 [Completed (IDEA)]

Ultraviolet Germicidal Irradiation for Transit Buses
[ TCRP J-04 (Innovations Deserving Exploratory Analysis--The Transit IDEA Program) ]

  Project Data
Staff Responsibility: Harvey Berlin

IDEA Concept and Product

This project incorporated ultraviolet germicidal irradiation (UVGI) into transit bus air conditioning systems. UVGI was tested for its ability to provide protection against harmful virus, bacteria, mold, and airborne pathogens for passengers riding on and employees working on transit buses. In addition, this project evaluated reduced maintenance costs on bus air conditioning systems by use of UVGI.


This project included testing and evaluation of UVGI systems on transit buses. Testing was done in cooperation with Houston Metro in Texas. Tests performed on the buses in­cluded elimination of virus, bacteria, mold, and fungi. In addition, laboratory virus testing was conducted to simulate bus conditions. Additional tests evaluated coil cleaning effective­ness, airflow improvement, temperature improvements, fuel savings, and reduced maintenance costs.

Completed Investigation

Prototype UVGI systems were designed and installed on the transit buses selected for testing. Three different models of buses required different mounting configurations and lamp sizes. The project tested and demonstrated the ability to use UVGI on different types of transit buses.


Buses were inspected and information relating to the test parameters was recorded. At the end of the test period, the information was compiled and evaluated by Biological Consulting Services Inc. and the investigators in cooperation with Houston Metro.

Project Payoff Potential

UVGI can help provide protection for passengers and transit employees against bioterrorism agents and common harmful pathogens like flu, viruses, mold, and bacteria on transit buses. UVGI can provide increased safety for mechanics while maintaining the bus air conditioning system. Maintenance savings of reduced fuel, increased component life, and less labor to maintain the air conditioning system were also found in the testing and evaluation.


The evaluation showed significant reductions of mold, bacteria, fungi, and harmful virus within the bus, which affect passengers, drivers, and employees. It also showed saving in maintenance costs with these systems.

Product Transfer

After testing on transit buses at Houston Metro, the results were evaluated. The evaluation and results are included in a final report for this project. The principle investigator will disseminate the findings via professional meetings and conferences. The application of UVGI for transit vehicles is patented.


The principal investigator has presented results of this project to individual transit agencies. Based on the successful results of this project, many transit agencies have purchased these systems and installed them in transit bus air conditioning systems.

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