Laurier Bike Lane’s Missing Data: a Reconstruction

Morning rush hour at Laurier Ave.
Morning rush hour at Laurier Ave.

Today, we will take a look at some Laurier Bike Lane data, because there was an odd dip in May. The data are collected in six different locations on the lanes between Bronson and Elgin. The counters are connected to a metal loop in the ground, which detects your bike’s metal. Every time someone cycles over the loop, it is detected and the ride is stored in the counter’s memory.

The data of two counters are submitted to a server at midnight, processed and put on line. The other data sets are collected on a regular basis in other ways. The data you can see on line are the totals of the eastbound and westbound lane counters near Metcalfe, i.e. two of the six counters.

You’ll notice that the weekend ride numbers are clearly lower than the weekdays (save torrential rain on a weekday  once in a while) which tells us that Laurier is a typical commuter route. By the way, in bike counter land, we talk about rides, not cyclists, as one cyclist could pass more than once.

Two odd weeks
But can you blindly trust the data to draw conclusions? Let’s take a look: The figure underneath show data from May 1, 2015 to June 19, 2015. The highs each week are around 2500/day, except two weeks, where the numbers were considerably lower.

Daily totals counted at Laurier Bike Lane at Metcalfe in both directions.
Daily totals counted at Laurier Bike Lane at Metcalfe in both directions.

Ah, rain, I remember that crappy month!”, the casual resident thinks. But is that true? Let’s take a closer look to the inbound and outbound data for the same period. We  immediately notice that the outbound numbers are a lot higher for a period of 17 days than the inbound numbers. Why is that?

The inbound and outbound data are very different for a few weeks
The inbound and outbound data are very different for a few weeks

Broken counter?
Is something wrong with the counter? No, not at all, it just didn’t count all the cyclists because there was construction going on in a section of the bike lane, so we are missing a whole bunch of rides. The actual stretch with the counter was open (hence the couple of hundred counts anyway), but many people bypassed the counter by getting out of the lane in advance or getting back in later (I am not sure anymore if the construction was right before or after the counter).

Missing rides
But how many did we miss?”, I hear you asking. Let’s extrapolate. Construction started on May 11 and ended May 27. During these days, 5980 rides were counted one way but no less than 14433 the other way. We know already that in normal circumstances  the numbers are pretty much the same in both directions (See below), so we can safely assume that we missed out on 14443 -/- 5980 =  8453 rides.

Capture 1 - Hans Moor
After construction, the in and outbound numbers are very similar again.

Four May Months

The total for May 2015 was actually closer to (42822 recorded total + 8453 unrecorded)  51,275 and that gives a much better result. For the record, these are the other “Mays”:

2012: 50,717

2013: 52,040

2014: 46,770

2015: 51,275 (educated guess)

We can ask  questions to predict growth: what if the weather had been warmer, would the counters have set a record for May? Or do we have growth, but colder weather kept people in the bus/car/home. A multi year weather data overlay would be fun, and not difficult to do, but that’s for another time. Companies like Ottawa’s own Klipfolio appear to do just that.

More cycling data online on Citizens for Safe Cycling’s special data web page : – data. More Ottawa cycling related data can be found on the 2014 Infographic.

Have fun on the bike!


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