Road program
Road

The Road program allows you to build road networks and run cars on them.

A computer literate three-year-old should be able to enjoy the program but they might be eight before they can consistently make non-contradictory layouts.

Construct road networks by selecting Road sections, Signs and Cars from the Palette to the main window.

Junctions and Traffic lights control the flow of the cars.

The Race menu item allows you to drive your own cars round the roads.

You can load and save your layouts.

If your games computer is old and slow, you might want to adjust the animation rate: press Ctrl-O for the Options dialog.

Although in all the examples, the cars drive on the left, this is not a restriction built into the program.


Road sections

Simple road sections behave as you would expect: the cars can only exit from the sections at the "open" ends.

There is nothing to stop cars entering a road section from the side but you will probably find it better to use a Junction.


Signs

Signs other than Traffic lights have no effect on the flow of Cars.

When you create a new sign in the main window, two signs may be drawn on either side of the selected Road section. However, if the squares on either side are filled with another road section, no sign will be drawn.


Cars

All cars move at the same speed. Cars can only move on the roads.

Junctions control the flow of the cars. Each section of road has only a few Exits. A car can enter a section from any direction but must leave through one of the Exits.


Palette

Contruct road networks by selecting Road sections, Signs and Cars from the Palette to the main window.

Select a road section, sign or car in the Palette then click in the main window. A copy of the item will appear in the main window. If you click on an existing item, it will be deleted.

The first two buttons on the Palette toolbar select the page of items. The third button shrinks the Palette window.

You can move the Palette by dragging its title bar.


Junctions

Junctions control the flow of the Cars. You should think of a section of road as having only a few Exits. A car can enter a section by any side but must leave through one of the Exits.

For instance, here are some sections and their Exits:

When a car is about to leave a road section, it chooses one of the exits at random. However, a car will never reverse direction and will only do a U-turn across two squares if it has no alternative. (The no U-turn rule prevents silly behaviour at junctions.)

Next Turn Left/Right

The "Next Turn Left" and "Next Turn Right" sections generally prime the car to turn left in the square if it can do so. For instance, if a car is approaching a T-junction, it could decide to turn either way:

You can force the car to turn right with a "Next Turn Right" or a one-way arrow:

"Next Turn Left" and "Next Turn Right" sections can also be used in combination with yellow boxes.

Yellow boxes

Yellow boxes are helpful in constructing multi-lane junctions.

Usually, when a car enters a yellow box, it can only exit in the same direction; it cannot turn.

However, if the car first passes over a "Next Turn Left" or "Next Turn Right" section, it is allowed to turn in that direction:


Traffic lights

Traffic lights affect on the flow of Cars.

When a car enters a Road section with Traffic lights and the Traffic lights are at not at green, the car will wait until the lights turn green.

All North/South Traffic lights are synchronised. All East/West Traffic lights are synchronised out of phase withe the North/South lights

When you create new Traffic lights in the main window, lights may be drawn on either side of the selected Road section. If the squares on either side are filled with another road section, no lights will be drawn but cars will still stop until the lights are green.

The lights follow the UK convention of

Red	stop

Red/Yellow	stop

Green	go

Yellow	stop

Red	stop


Load
Load and save

Road layouts are automatically saved when you exit the program or load a new layout.

You can load and save your layouts with the File|Open and File|SaveAs menu commands in the Palette window.

Simplified File dialog boxes are used so as not to confuse younger users.

When you next start the program, it will load the file you were last working on.

The File|New command empties the layout and sets the filename toan unused name or  "Road15.rd".


Options dialog

The Options dialog allows you to change the animation rate:

Frames	the number of times a car is redrawn when moving between squares.

Period	the animation period in units of 55mS

Direct to Screen	the cars are drawn directly onto the screen rather than to a hidden buffer


Race

You can drive and race your own cars around the roads.

Select the Race menu item.

You can now place race starting-grids on your road layaout.

Each checkbox puts a different racing car onto the layout on a starting grid (if one is present).

Each racing car can be controlled by a different set of keys. Click the Keys button and select the control keys you want.

Select the number of laps you want then press the Start button.

To change the way the cars handle, press Ctrl-H.