Bear Lake Rd. is currently closed for maintenance from 9 am to 4 pm, Monday through Friday. It is open at all other times.
You can drive up before 9 am, and you‘ll still be allowed to return during the maintenance window - it‘s just that they won‘t allow any new vehicles to go up during that time.
You can also park at the Moraine Park area (1 mile in to Bear Lake Rd.) and take the visitor‘s shuttle up to Bear Lake, though there can be delay of up to 2 hours on the shuttle during peak visiting time.