Seeing this, I asked the Office of Court Administration for statewide data on the number of non-parking traffic cases filed in municipal court to update this Grits post where I compiled similar information a couple of years ago. (These numbers don't line up precisely with the Dallas PD data, but give a sense of the statewide trend in an apples-to-apples format.) Here's the updated chart:
Notably, I'm told Fort Worth hasn't reported their data to the OCA since the reporting format changed beginning in FY 2012, and San Antonio only reported four months of data for FY 2013, so I didn't include their numbers for that year. (McKinney, not depicted, also has not reported since 2011.)
According to the municipal court data, traffic tickets in Houston declined nearly as much as in Dallas, with Austin not far behind. One also notices that much-smaller El Paso now hands out many more tickets than either the capital or Dallas (probably because near the border police are using traffic stops as a pretext to search for contraband and south-bound drug money). Tyler's numbers stand out; considering my hometown's population was just under 100,000 in 2013, almost 67,000 is a huge number of tickets on their part. And Lubbock's increase is particularly puzzling - they, and to a lesser extent Garland, and Plano, appear to be bucking the statewide trend.
I can't explain why Dallas PD reported writing 20.5% more tickets in 2013 than there were traffic cases filed in municipal court, but I'm sure there's some good explanation. The other source of data on traffic citations - coming directly from departments, as in Goldstein's story, as opposed to the municipal courts - would be racial profiling reports submitted to TCLEOSE. But not wanting to pay for (or wait for) the open-records requests, I'll leave that to somebody else to compile.
As was the case the last time we discussed this, I can't think of a good explanation for what appears to be a statewide trend toward writing fewer traffic tickets. A number of commenters offered interesting hypotheses two years ago, but nothing you could really hang your hat on. Let me know in the comments below why you think the number of traffic tickets in Texas' large cities is declining.
If your city isn't depicted in the above chart see the OCA municipal court data for 2010, 2011, 2012 and 2013.