Advanced Accident Hot Spot Identification In 9.3

[DanielHitchcock]

Hi.

Firs time post on here.

I am having trouble working out a way to identify accident hot spots on our network that meet the specifications of my company.

The calculation that my company uses to work out hot spots is as follows:

>=9 accidents within a 100m radius over 3 years

Is there a way that I can achieve this, using standard tools found in the ArcToolbox?

My initial thoughts are using one (or a combination) of the below:

• Buffer


• Dissolve


• Collect Events


• Integrate

Can someone point me in the right direction?

Thanks!

Dan.

[JaySandhu]

You can use the Network Analyst solver OD Cost matrix to load all you accidents as origins and destinations. Then bring up the properties of the OD layer and set a cutoff of 100 meters (assuming you have a length impedance attribute in meters) and turn off hierarchy if it is on. Then solve.

The output lines table will have a list of distances between each accident. There is a DestinationRank field that shows how many destinations were found for each Origin. You can select rows based on DestinationRank > 8 and then use this to further qualify if they happen to be within your time frame.

Hint: Add a date field to the Origins/Destination attribute tables and then at LoadLocations time map the date/time to this date field so that you have access to this information after your solve.

Jay Sandhu