The slowest I've ever seen was 5 MPH, but this was on private property.
55
Vadodara to Jambusar is the slowest train in India running @ 11 KM/Hour Speed. and taking 3.5 hours to complete 44KM stretch. Nilgiri express is officially slowest train running @ 10 KMs/Hour speed, but it is running in Hilli region and speed limit is obvious for it.
The slowest speed an object can move is zero.
the Elmatross is the slowest
The legal posted limit plus 5, or as fast as the slowest car in the long line of traffic in front of you.
about 9.3 mph
There are several Interstate Highways with a 75 MPH speed limit at various points throughout their span, but there isn't one which has that speed limit at every single point.
45
In the US, the maximum speed on an interstate highway is 70. Until recently, there were a couple of stretches of highway that were limitless.
FASTEST when dealing with speed
the slowest animal only moves 10 Centimetres per minute
Monkeys