LOGO-L> road_rules

[KERRB@Magill.UniSA.edu.au]

ROADRULES

I have trialled a road rules simulation in MicroWorlds. The original
suggestion was from Julie Clune (Woodlands CEGGS). I jumped at the idea
because I thought it would really motivate kids. 

In the first lesson that I introduced this topic one student who had
hitherto been poorly motivated and inarticulate suddenly found his voice
and explained clearly to the class and me the hierarchy of give way
rules. I knew then that I was onto a winner.

What he said was (comparisons with other countries may be interesting)
that the correct order in deciding whether or not to give way was:-
1. pedestrians
2. traffic lights
3. Tee intersection
4. right
5. breaking into traffic
6. left turn before right turn


Nevertheless, it proved tricky to program situations where cars might
collide and students needed lots of help here, which is why I have
developed the code below.

I also received a question from Janette Emerson about a similar program 
involving
pedestrians crossing at lights. I think what I have coded below could be
adapted to that. 

Here are the procedures to simulate cars meeting at a T intersection.
The procedure controlling the car starting on the left of the T is
called west (turtle t3); the procedure controlling the car on the right
of the T is called east (turtle t1); the procedure controlling the car
starting at the bottom of the T is called north (turtle t2).

You need a button called go and another called reset.

You need 3 sliders, called speed.west, speed.north and speed.east, all
set on a maximum of 5. The procedures that follow use the timer to
change the speeds of the car randomly to make it more realistic. One
consequence of that is that backend collisions as well as collisions at
turns are possible too. This just arises naturally out of varying the
car speeds randomly.

If a collision is about to occur the test procedure stops everything and
asks the question: who should have given way?

That is as far as I have gone so far. This is written for MicroWorlds
version 1.

I's be interested in ideas about developing this program further or 
adapting it to similar situations -- it a natural self motivator for 
older kids in particular.

-- Bill Kerr

to go
forever [test]
launch [west]
launch [north]
launch [east]
end

to west
 t3,
 if xcor > -6 [seth 180]
 if ycor < -140 [reset.west]
 vary.speed.west
 launch [ fd speed.west]
west
end

to vary.speed.west
if timer > 9900 [resett]
if (remainder random timer 100) = 0 [setspeed.west 1 + random 5]
end

to north
t2,
if ycor > 37 [seth 90]
if xcor > 250 [reset.north]
vary.speed.north
launch [fd speed.north ]
north
end

to vary.speed.north
if timer > 9900 [resett]
if (remainder random timer 100) = 0 [setspeed.north 1 + random 5]
end

to east
t1,
if xcor < -7 [seth 180]
if ycor < -150 [reset.east] 
vary.speed.east
launch [fd speed.east]
east
end

to vary.speed.east
if timer > 9900 [resett]
if (remainder random timer 100) = 0 [setspeed.east 1 + random 5]
end

to reset.west
t3,
setpos [ -200 40] seth 90 setspeed.west 5
end

to reset.east
t1,
setpos [287 -2 ] seth 270 setspeed.east 5
end

to reset.north
t2,
setpos [-68 -147] seth 0 setspeed.north 5
end


to reset
cc
resett
t1, reset.east
t2, reset.north
t3, reset.west
end

to test
t1, if (distance "t2) < 25 [cc show [who should have given way?] stopall]
t1, if (distance "t3) < 25 [cc show [who should have given way?] stopall]
t2, if (distance "t3) < 25 [cc show [who should have given way?] stopall]
end


-- Bill Kerr
---------------------------------------------------------------
Please post messages to the Logo forum to logo-l@gsn.org.  Mail
questions about the list administration to logofdn@gsn.org.  To
unsubscribe send    unsubscribe logo-l    to majordomo@gsn.org.