Being at the right at the right time is crucial for your and others safety as well as the legal implications.
The best way to work out what the speed limit is:
Built up area
Look around can you see buildings and lampposts?
If so, it is a built up are. The speed limit then it is a 30mph if it is any other speed their will be signs telling you.
These signs can be found either at the start of the road you are entering, the end of the road you are leaving or a change in road type for example from a single to a dual carriageway.
Look around are their very few buildings and no lampposts?
If so then it is a National Speed Limit road unless there are road signs telling you a different speed.
There are 2 speeds for this:
60 mph- Single Carriageway.
A single carriageway is a road which has no centre dived from oncoming vehicles. This means other than a white line there is no grass kerbs or barriers. It can be more than one lane in each direction.
70 mph- Dual Carriageway or Motorway.
A Dual Carriageway is a road which does have a centre divider from oncoming traffic. Their will be a Kerb, Grass, Barrier or all of them dividing you from on coming traffic. This could be 1 or more lanes in each direction.
Know you’re at the correct speed; think how many times you check your mirrors?
Every time you check your mirrors check your speedometer.
Take into account up and down hill gradients
Pedestrian levels such as outside a school at certain times of the day
Clearance. You have to give for every 1 foot or 30 cm you get closer to an obstacle such as a parked car reduce your speed by ¹/3. i.e. 2 feet clearance 20mph, 1 foot clearance 10mph etc
Most important of all is to match your speed to the distance in which you can see it is safe to stop!
On your driving lessons all of Homer’s Instructors are specifically trained to teach you how to be at the correct speed and how to drive at high speeds when appropriate.