# Modelling

• May 13th 2009, 09:57 AM
Cairo
Modelling
Not sure if this thread belongs here, but I couldn't see anywhere else to put it.

I've been asked to create a mathematical modelling report on the following and would like some help please.

A two lane road has been made one-way to create additional parking. Parking is allowed on the LHS, whilst traffic is free to move on the RHS. Most of the parking space is occupied during the day and pedestrians are finding it difficult to cross the road safely.

A pedestrian crossing will be installed to help with this and zigzag lines will extend before the crossing to indicate no parking. This helps approaching traffic view if anybody is waiting at the pedestrian crossing. The drivers vision is obscured if a car is parked too close to the crossing.

The problem is to find how far the no parking zone lines should extend before the crossing. There is still a shortage of parking, so while the no parking lines should be long enough to achieve safety, they should not be longer than necessary.

I'm assuming the stopping distance will be needed here, d=kv+lv^2 (k,l are constants). WHat about trigonometry for vision?

Any help in formulating the model would be great.
• May 13th 2009, 02:22 PM
CaptainBlack
Quote:

Originally Posted by Cairo
Not sure if this thread belongs here, but I couldn't see anywhere else to put it.

I've been asked to create a mathematical modelling report on the following and would like some help please.

A two lane road has been made one-way to create additional parking. Parking is allowed on the LHS, whilst traffic is free to move on the RHS. Most of the parking space is occupied during the day and pedestrians are finding it difficult to cross the road safely.

A pedestrian crossing will be installed to help with this and zigzag lines will extend before the crossing to indicate no parking. This helps approaching traffic view if anybody is waiting at the pedestrian crossing. The drivers vision is obscured if a car is parked too close to the crossing.

The problem is to find how far the no parking zone lines should extend before the crossing. There is still a shortage of parking, so while the no parking lines should be long enough to achieve safety, they should not be longer than necessary.

I'm assuming the stopping distance will be needed here, d=kv+lv^2 (k,l are constants). WHat about trigonometry for vision?

Any help in formulating the model would be great.

What is the speed limit on this road?

Compute the stopping distance for a vehicle at the speed limit.

Now draw a picture showing the geometry.

You may also need to know the nominal distance of the outside edge of a parked car from the curb and how far back from the curb the pedestrian waiting at the crossing will stand.

CB
• May 13th 2009, 09:39 PM
Cairo
Thanks.

We are not given a speed limit. The model needs to be set up from scratch and should apply to a raod at any speed. So in this instance speed is a variable.
• May 13th 2009, 10:14 PM
OnkelTom
The speed limit will have a massive impact on stopping distance and therefore how early a driver needs to see the crossing! I would find out what the speed limit is in you're state for a one way road with parked cars along in an urban area and work off that, possibly in the region of 30mph? Around here, some urban areas have started to be redesignated as 20mph, so possibly this is something you could investigate- whats needed for the two speed limits and how by lowering it and introducing measures to ensure people do (cameras, sleeping policemen, etc) you can gain more average car parking space, which you said was at a premium.

I mean, you can't stop people speeding if they really want to, but at the same time it would be bonkers to work under the assumption people will bomb along at 80, otherwise you will need half the road clear for them to stop!

Another thing i would suggest is for super saftey, find out if wet conditions make much difference (stopping times and visability), and perhaps factor this in?#

Sounds alot more intresting than our modelling assignments, which unforunatley revolve around stats all the time it seems :(!!!!
• May 14th 2009, 08:08 AM
Cairo
Thanks for all your thoughts so far.

As mentioned, the model does not assume a speed limit. Although figures could be used to check that the model actually reflects real life or if revisions are needed.

My stumbling block right now is how to start setting the model up. The geometry of the drivers vision needs to be kept simple for a first model and I cannot think of where to begin!
• May 14th 2009, 12:17 PM
CaptainBlack
Quote:

Originally Posted by Cairo
Thanks for all your thoughts so far.

As mentioned, the model does not assume a speed limit. Although figures could be used to check that the model actually reflects real life or if revisions are needed.

My stumbling block right now is how to start setting the model up. The geometry of the drivers vision needs to be kept simple for a first model and I cannot think of where to begin!

Have you drawn a picture?

CB