The fire at the centre in Risk Street, Dumbarton broke out on January 1 and has been described by Police Scotland as a ‘deliberate act’.
Scottish Fire and Rescue Service attended the scene and managed to put out the fire.
Police added that no-one was injured and the incident has not affected test services at the centre.
Officers are investigating and police have appealed for anyone with information to come forward.
Detective Constable Thomas O’Donnell urged anyone who may have seen or heard anything regarding the incident to get in touch: “We are in the process of reviewing CCTV footage from the area and the surrounding area and I’m confident it will provide useful information on the suspect and the incident. However, I would like to appeal to anyone who may have seen or hear anything suspicious to contact us.”