Fines kick in for endangering SA cyclists

South Australian drivers will be fined almost $350 for overtaking cyclists unsafely after a three-month grace period for the new road rules.

Motorists must leave a gap of at least one metre when passing cyclists in speed zones of up to 60km/h to help reduce accidents, police say.

When the speed limit's 60km/h or more, drivers must leave a 1.5 metre gap.

The changes were introduced in October with a three-month cautionary period for drivers to adjust.