OK, (sentence)

Use "OK" at the beginning of a sentence when you're starting a new thought. It has a meaning like "Now I'm going to start..."

the light

When you're talking about driving on a street, the phrase "the light" usually refers to a traffic signal. For example:

I think we were supposed to turn at the last light.

You can let me out right after the light.

head (somewhere)

"Heading" somewhere means starting to move in that direction. You can "head" in a certain cardinal direction:

Head north.

Head southwest.

Or you can "head" toward a place:

I think I'd better head home.

Can you head toward the Fashion District?

Let's head that way.

And you can "head" in a direction "on" a road or street.

Head west on Houston Street.

Highway (number)

A "highway" is a road that drivers can drive quickly on with few stop signs or traffic lights.

In the U.S., a lot of highways are given numbers. People refer to them like this:

I'd take Highway 95 if I were you.

The two directions of a highway are usually marked as "North" and "South" or "East" and "West":

Merge onto Highway 38 North.

turn (in a direction) (somewhere)

When you're giving directions, you may need to tell someone where to turn:

Turn right at the corner.

Turn left at the second intersection.

an overpass

An "overpass" is a place where a road goes over something, like another road or some train tracks. We build overpasses so that traffic can go in different directions without stopping.

When a road goes over a river or other body of water, it's not an "overpass"; it's a "bridge".