# Reading the Frequency Map for average travel times

March 7th, 2013

Here’s a little known feature of the Transit Frequency Map that’s worth pointing out. You can determine your approximate total travel time, including waiting, without having to look at a schedule. Here’s how:

• Find the line or corridor you need.
• Determine it’s approximate frequency.
• Divide that in half to get the average wait time.
• Find the travel time by counting the white dots between your origin and destination. The distance between two dots represents about 10 minutes of travel.

Let’s walk through an example. Get your map out:

We’re going from Downtown to the College Hill business district on a weekday afternoon. We’ll need to use the #17. Look at the legend and compare the line thickness to find the #17’s approximate frequency.

It looks like it comes about every 15 minutes on average. Half of that is 7.5 minutes, but let’s be pessimists and round it to 8.

That’s 40 minutes plus the 8 minute average wait, meaning a total of 48 minutes for our trip. A quick schedule check confirms this is about right. You can also get a worst-case scenario by assuming you just missed a bus and using the whole frequency value without dividing it. If the longest you can wait is about 15 minutes, the longest your trip will take is about 55 minutes.

Remember, this isn’t exact since traffic speeds and frequencies vary by time of day. But generally, It’s pretty accurate. Try it out for your normal trip and see if it works for you…Then try a new one! It’s important to note that where lines are redundant, like the #4 and #11 are between Downtown, you can add their average frequencies together and get a lower average wait time because you can take whichever one comes by first.

### 3 responses to “Reading the Frequency Map for average travel times”

1. its easy AND fun!

2. Jeffrey Bridgman says:

Very nice! That white dot is an incredibly useful device in this context!

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