# Increasing speed limit by 35 percent in ArcGIS Field Calculator?

I have a network with a speed limit attributes.

I want to increase the speed limit by 35 percent in order to run an analysis for an ambulance.

For example, if the speed limit is 60, I will increase it by 35 percent.

Can I do this in the field calculator?

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## 2 Answers

You can do it in the field calculator by simply selecting that field (let's say it's `SPEEDLIMIT`) and saying it should now be equal to `[SPEEDLIMIT] * 1.35`.

(Better data management is to make a new column, e.g. `AMB_SPEEDLIMIT = [SPEEDLIMIT] * 1.35`, so you won't lose the original speed limit data, but that really depends on how much you plan on using this network in the future and whether it'll ever be used by somebody else who doesn't know the speed limit was increased, etc.)

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Thanks for your help But is there any way to post an increase in speed by 35 percent compared to the speed limit in a New Service Area Analysis that I may not destroy my network? Regards Tom Anders – user15888 Mar 7 '13 at 13:47
This should do so. You have your original speed limit in one field, and the higher limit in a seperate field. – HeyOverThere Mar 7 '13 at 13:56

You could try multiplying the column by `1.35`.

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Thanks for your help But is there any way to post an increase in speed by 35 percent compared to the speed limit in a New Service Area Analysis that I may not destroy my network? Regards Tom Anders – user15888 Mar 7 '13 at 13:43
@user15888 Can you create a new field where you just follow Erica's solution? – dassouki Mar 7 '13 at 13:46