Determining optimum flash patterns for emergency service vehicles: An experimental investigation using high definition film
The 4Hz flash rate was perceived to convey greater urgency than 1Hz rate. The 1Hz single pulse pattern was ranked least urgent of all the combinations. Estimates of minimum space acceptable for pulling out reflected urgency measures. Less risky gap acceptance judgements were evident for the 4Hz single pulse combination. HD film was found to be a low-risk, valid method for assessing EVL efficacy.
flash pattern emergency service vehicle lighting urgency perception