April 5


Traffic Count Trick – Oil Your Padlocks

By Mike Spack

April 5, 2016

graphite oil, padlock, Traffic Counting, tube counters

Padlock and ChainTom Sachi from SRF Consulting Group was telling us about a big problem they had with their tube counters out at the Minneapolis St. Paul airport. The airport uses so much salt on the roads that SRF’s padlocks end up corroding/sticking and they couldn’t get them open this winter. They had to cut their chains to get the tube counters free.

We haven’t experienced this extreme example, but our padlocks do start to stick over time.  The solution is to use a graphite based penetrating oil to lubricate the mechanism. Here’s a $6 tube from Amazon.

I recommend putting a few drops in each of your locks once a year (we’ve been doing this for a decade).  This will clean the locks out, lubricate them, and generally keep them in good working order.  You can buy bigger jugs of the oil and submerge the whole lock in extreme cases – but then you have to get the lock wiped down after you take it out.

I also recommend keeping a tube of this oil in your work truck in case of emergencies.  My hunch is that a few drops would have cleaned out SRF’s padlocks at the airport to get them working.

P.S.  I had a backdoor lock that was hard to open. This oil smoothed it right out.

  • Have you had any experience in people including kids jumping on your tubes to activate them? On some sensitive job the local residents can try to affect the counts by driving over them or jumping on the tubes. Any experience in this situation?


  • Bob – This could happen, but you should be able to filter this out if you collect a weeks worth of data. They’re not going to be out there 24/7. If you’re set up for speed classification data with two tubes, the kid stomping on a tube will be automatically filtered out of the data set by the software. Mike

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    Mike Spack

    My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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