Mine varies with traffic speed. At 60 mph, it's about 2x-3x the distance as at 30mph. It defaults to Long, but Short is best for Seattle-area driving.
From the manual: Select a distance from the table below. Note that the distances shown correspond to a vehicle speed of 50 mph (80 km/h). Vehicle-to-vehicle distance increases/decreases in accordance with vehicle speed.
Long ~160 feet
Medium ~130 feet
Short ~100 feet
(160 feet ought to be enough for anybody - almost every modern car and truck has a 60mph to 0mph braking distance under 160 feet on dry pavement. This car's braking distance is 125 feet, so Medium follow distance keeps you far enough behind a car that you could stop entirely in the gap.)
From the manual: Select a distance from the table below. Note that the distances shown correspond to a vehicle speed of 50 mph (80 km/h). Vehicle-to-vehicle distance increases/decreases in accordance with vehicle speed.
(160 feet ought to be enough for anybody - almost every modern car and truck has a 60mph to 0mph braking distance under 160 feet on dry pavement. This car's braking distance is 125 feet, so Medium follow distance keeps you far enough behind a car that you could stop entirely in the gap.)