WA's top traffic cop has pleaded with motorcyclists to change their bulletproof mentality, with a new analysis showing riders are at greatest risk late in the afternoon on weekdays.
A review of serious motorcycles crashes over almost 20 years found two three- hour windows.
Between 1995 and April 1 this year, 524 people died and 984 were injured in motorcycle crashes.
Of 1447 crashes between Monday and Thursday, most were between 3pm and 6pm.
On Fridays, most were between 6pm and 9pm, though 3-6pm was still prominent.
At weekends, motorcycle crashes were spread across the day.
Assistant Commissioner Nick Anticich said motorcyclists and drivers needed to remember dangerous or distracted riding and driving could be fatal.
He said people needed to consider they might be tired after work and not rush to get home.
A Mt Lawley man, 26, was in a critical condition in Sir Charles Gairdner Hospital last night after coming off his Harley-Davidson in City Beach on Thursday.