What to Consider When Buying an Automatic Vehicle Traffic Recorder (Tube Counter)
You need to accurately collect vehicle traffic data on roadways in your jurisdiction, or for your clients, over the course of several days or even weeks. You’re looking for the right tube counter to get the job done without spending more money than you need to.
After 25 years in the traffic counting business (and traffic engineering as a PE and PTOE), here are 18 things I recommend you consider:
- Data Types: There are two types of tube counters (a) totalizers that take the number of axle strikes and divide by two to approximate the vehicles and (b) loggers that timestamp each axle hit and translate those recordings to per vehicle classification with their travel speed. If you have an entrance to a park, you can get away with a totalizer. If you are a government engineer, consultant, or data contractor studying roads, go with a timestamp logger that will provide more accurate data and richer datasets.
- Accuracy: Traffic volumes can vary more than 10% daily on the road, so traffic engineers end up smoothing traffic count data with daily and seasonal adjustment factors. And the thresholds within volume/capacity ratios are thousands of vehicles. So we don’t need precise, 99.99% accurate data. Modern time stamp classifiers all claim to provide 95%+ accurate data, which is accurate enough.
- Size: Counters range in size from a pack of cards to a ten-pound shoebox. The ten-pound shoeboxes haven’t been modernized and take up a lot of space/weight. A power user will install 30-40 counters per day, so size and weight do matter.
- Hardware Cost: There are three kinds (a) the totalizers cost a few hundred dollars, (b) shoeboxes cost around $1,000, and (c) the timestamp recorders that weigh under a pound cost under $500.
- Software Cost: They range from free to several thousand dollars. Some processing software takes several days to learn, and they claim to produce more accurate traffic data. See above about Accuracy. You can make it as complicated as you want, but there is a difference between accuracy and precision. Most users don’t need complicated (expensive) software.
- Durability: Talk to the manufacturer, but all counters should last years under normal use. And none of them will survive an extreme run-in with a snowplow or lawnmower.
- Setup Verification: Counters have no indication, LED light indications, or digital displays to show you pulses from vehicles when the counter is setup. You don’t need to spend extra money on the digital displays, but an indication it is working is useful.
- Data Storage: Data storage is cheap. The counter should be able to store millions of vehicles over several years. Be wary if they cannot. But you will want to regularly delete data off the device as too much historical data on the device will slow down uploading/ downloading.
- Weather Resistance: You won’t be able to submerge the counter in a pond and have it work. It might not work in the heat of the Gobi Desert or cold of Antarctica. But I believe all counters currently on the market will perform in average weather conditions.
- Battery Charging: Some have solar panels. Some have batteries built in that will last years but aren’t replaceable or rechargeable, which makes the counters disposable. Some have chargers to keep the batteries powered. Charging the devices is a pain. But disposable counters might not be cost-effective. Some way of using the device for a month or two and then charging/swapping batteries is my preference.
- Recording Duration: More than 95% of counts done with tube counters are trying to get 24 or 48 hours of data. Occasionally a week or two might be needed. Consider more permanent types of counters if you need more than two weeks of data at a location. Define what you need and then make sure the file storage and battery life will provide for that need.
- Downloading: You just read the number on a totalizer, so there’s no downloading involved. Most timestamping counters have download cables and processing software on your computer. The modern countPULSE sends data from the counter through your phone via an app while you pick up the tubes and sends the data to a cloud-based system where the end-user can download data reports. This process eliminates the traditional downloading step.
- Data Report Configuration: This is how flexible the reporting software is and how many options it provides. Again, do you need a Chevy or a Ferrari?
- Location Programming: The totalizer and data loggers (like the Pico) don’t have any programming. The Apollyon lets you enter site data into the logger with a touchpad/digital display. The countPULSE lets you enter site data into the phone app, providing this feature without the cost.
- Mini vs. Heavy Tubes: There are two main types of tubes, and the difference is how thick the rubber wall is. All brands of counters I know of work both tube thicknesses, so it’s a preference. I prefer mini-tubes, which are cheaper and much lighter. They wear out faster, but are a lot easier to install.
- Company Reputation: Self-explanatory.
- 2 vs. 4 Channel: All tube counters can accurately count two-lane roads (and generally three-lane roads that have a turn lane in the middle). 4-lane undivided roads are complicated, and some counter models have configurations to install four tubes across the street for this situation. I prefer to install a two-channel counter with the tubes stopping in the middle of the road instead of going across the four lanes. Then I put a separate two-channel counter on the other side of the road. This setup ensures you aren’t paying a lot extra for features that are used 1 out of 100 times.
- Bike Counting: Most counters will pick-up bikes if you use short tubes across a bike trail. Some brands are tuned in to provide 95%+ accurate counts of bikes. Counting bikes and vehicles at the same time is challenging because an algorithm sensitive enough to pick up a bicycle will generate tremendous noise when driven over by a semi-truck.
Tube Counter (aka Automatic Traffic Recorders – ATRS or Vehicle Classifiers):
I was frustrated with the cost of tube counters and the time wasted in the downloading process, so I developed the countPULSE tube counter with the professional product designers at Tomorrow Lab. If you’re interested in learning more about the phone app controlled countPULSE, you can download the countPULSE spec sheet here. And mention MikeOnTraffic during the purchase process to get 20% off your first order of $299 countPULSEs (minimum order quantity of 5). Here’s to safe, accurate traffic counting!