However, exactly as things are now, this does not make the older population worse drivers as demonstrated by the attitude of the insurance companies.
Older drivers, as a group, drive fewer miles. They do so on lower speed roads, and they are less likely to drive at night. The main factors for expensive accidents are speed and visibility, and the main scaling factor for risk is miles (drive twice as far and, all other things being equal, you'll have twice as many accidents).
That makes older drivers a better insurance risk.
However, if it's 3pm on a sunny Thursday afternoon and the roads are full of drivers of various ages, then the older drivers are most certainly not safer than the middle-aged ones. Older drivers' insurance rates don't drop remotely as much as their mileages do.
Older drivers' risk per mile of accidents is higher.
The overall effect of those accidents is lower, because they are (on average) lower energy.
The overall number of accidents they have is lower than their fifty year old neighbour, but not as lower as the difference in mileage implies.
In summary, they are more dangerous per mile, but drive fewer miles.
Research work (US, but there's little reason to believe it's different here). It's very complex to unpick all the possible factors, as this shows.
www.iihs.org/iihs/topics/t/older-drivers/qanda
"Older drivers have low rates of police-reported crash involvements per capita; their per capita fatal crash rates begin to increase at age 70. Per mile traveled, crash rates and fatal crash rates also start increasing at about age 70. Some caution should be used when comparing crash rates per mile traveled of different age groups. Older drivers generally travel fewer annual miles than most other age groups and, similar to low-mileage drivers of other ages, they tend to accumulate much of their mileage in city driving conditions. In contrast, drivers who accumulate more miles tend to drive more on freeways or divided multilane roads, which generally have much lower crash rates than other types of roads. Hence, the elevated crash rates for older drivers when measured per mile traveled may be somewhat inflated due to the type of driving they do. 15
Insurance claims provide another view of crashes of all severities. Property damage liability claims are filed when an at-fault driver damages someone else's property. Collision coverage insures one's own vehicle against loss caused by a crash. Drivers ages 60-64 have the lowest rates of property damage liability claims and collision claims per insured vehicle year. Rates start increasing after about age 65, and rise above rates for middle-aged drivers at about age 80. However, older drivers' insurance claim rates are much lower than rates for the youngest drivers."