Andy Larsen: Need help deciding where to live? These maps can help.

Maybe this makes me a fool, but I didn’t know about isochrones until recently. Now that I do, they’ve changed the way I think about living in the Salt Lake Valley.

Isochrones are maps that depict areas accessible from points within certain times using certain modes of travel.

Think about them as kind of reversing the questions asked in your typical Google Maps search. There, you want to figure out how many minutes it will take to get from point A to point B. Isochrones show you how many point B’s you can get to in so many minutes from point A.

OK, maybe that’s more confusing than just showing you how they work. This article includes a bunch of different uses for isochrones, ones I thought revealed interesting things about living in the valley. Truthfully, though, the way you’re going to get the most out of isochrones is by playing with the technology yourself — by seeing how far you can go from your house, your office and so on.

In my exploration, probably the most user-friendly website where you can create your own isochrones is app.traveltime.com. Simply type in your starting point, choose how much time you have, and a preferred mode of transport. You can also layer different maps to compare and contrast. That’s how we created the following:

Comparing driving, cycling and public transit

Isochrones are particularly useful at showing how effective various modes of transportation are in various cities. In New York, for example, public transit is often more effective than driving from one point to another.

In Salt Lake City, though, cars rule. For example, from downtown’s Temple Square, here’s how far you can get by driving, compared to cycling or public transit in 30 minutes of travel time.

You can see how the Utah Transit Authority’s system has worked here: TRAX can take you south to 3900 South, while the 455 UTA bus can take you north to North Salt Lake. Truth be told, you can get farther east and west, if you’re willing to bike, especially if you have to travel diagonally.

Meanwhile, you certainly can get farther than that by driving. But you still can’t reach much of West Jordan, South Jordan and Sandy in a half-hour from Temple Square.

If you go to the TravelTime app, you can also play with trade-offs. Public transit does allow to you get some time back when compared to driving or cycling: You can work or read while on a bus or train. So maybe it’s worth it to have an hourlong public transit ride vs. a half-hour drive. (Of course, saving on auto pollution matters, too.)

Comparing heavy traffic to normal traffic

Isochrones also show the impact of traffic on a commute. In the TravelTime app, you can pick which times you want to examine. Here, I’ve chosen the distance you can travel from Temple Square in a car at noon, in a low-traffic time versus the distance you can travel at 4:45 p.m., a relatively high traffic time. Traffic is variable on a day-to-day basis, of course, so this map uses averages.

It’s a smaller difference than in many cities, but still you can see the impact car traffic has on travel in the valley. In particular, reaching the south end of West Valley City or Kearns becomes harder — as does getting to much of Holladay, Midvale or Sandy.

Comparing 20 minutes to 30 minutes to 40 minutes

How long of a commute is OK with you? Personally, given my role as a Utah Jazz reporter, I might not want to be more than 15 minutes away from Vivint Arena. On the other hand, with the cost of real estate higher than ever, I’ll probably have to make trade-offs if I want to buy a house one day.

Here, again, I use Temple Square as our starting point. How far can you get in 20 minutes — versus 30 minutes or 40 minutes — in a low-traffic scenario?

There’s a lot of real estate in the valley’s south end, to be sure, but it might take longer to get home from downtown than if you lived in Farmington. Heck, an enterprising real estate agent might use these isochrones to find the most undervalued areas in the Wasatch Front.

Likewise, if you were starting or running a small business that relied on customers getting to a store, this tool could show how large your core customer base might be, and who might be realistically out of reach.

Comparing places to live in Salt Lake City without a car

Now let’s shift from downtown and our car-centered mentality. Where in Salt Lake City is public transit most effective? Here, I’ve compared three neighborhoods: How far can you get in 30 minutes from the Utah State Fairpark in west Salt Lake City, LDS Hospital in the Avenues, and the east side’s Sugar House Park?

Living in the Avenues provides the biggest area reach of the three options, giving access to points on the west side and Sugar House. From Sugar House Park, it might take 45 or 50 minutes to reach downtown hubs, while Fairpark living means a much shorter commute. Honestly, though, there are strengths in each of those three options.

Again, it’s easy to imagine this data being super helpful when deciding where to live. Typing in an address or nearby landmark can quickly show how feasible car-free travel might be from a proposed apartment or house. Urban transportation planners can also use this mapping to see how equitable public transit options are across the Wasatch Front.

These are just some examples of how isochrones can prove interesting, but there are many more. Again, the way you’re going to get the most out of this is by trying to build the maps yourself and answering the questions specific to your particular circumstances.

Andy Larsen is a data columnist for The Salt Lake Tribune. You can reach him at alarsen@sltrib.com.

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