Speeding While Black? Assessing the Generalizability of Lange et al.’s (2001, 2005) New Jersey Turnpike Speeding Survey Findings

Abstract

Across three months during 2001, Lange, Blackman, Johnson and Voas collected data from the New Jersey Turnpike to determine whether there were differences in speeding behavior grounded in race and ethnicity, while controlling for age and gender. They reported that Black drivers were more likely to speed at high rates (15 mph or more over the speed limit) in 65 mph speed zones, as were young drivers and male drivers. In the scholarly report of their research, Lange and colleagues concluded: “our research offer[s] a plausible explanation for the findings that Black drivers are represented among traffic stops at a higher rate than they are represented in the population.” The present research assesses the generalizability of the findings reported by Lange and colleagues using data reported by Massachusetts State Police officers during April and May of 2001. We also find that Black drivers, young drivers, and male drivers are more likely to speed at high rates in 65 mph speed zones. We therefore remind scholars that Lange and colleagues’ findings and our own are entirely consistent with theory and research on the correlates of law violative actions. Our fundamental conclusion, however, is that more research is needed to determine whether traffic stops for Driving While Black are in small part the result of Speeding While Black.

Keywords:

• age
• gender
• race and ethnicity
• high rate speed zones
• high rate speeding

Notes

1. A data set involving tickets, but not written warnings, across approximately three years was eventually assembled (see Farrell, McDevitt, Bailey, Andresen, & Pierce, 2004).

2. The data were found at www.boston.com/globe/tickets/warnings.zip and the codebook was found at www.boston.com/globe/tickets (retrieved and downloaded March 6, 2004). The data and codebook are no longer retrievable. We would be pleased to provide copies of both.

3. To isolate night stops, we began with the officers’ reports of the hour of the stop and whether it was a.m. or p.m. Because officers did not report the minute in an hour when a stop started (e.g., a stop reported at 4:00 a.m. could have started at 4:01 a.m. or 4:59 a.m.), we assumed that all stops on the cusp of daylight were day stops. With that assumption in place, we next used civil twilight (the times immediately after sunset and immediately before sunrise when objects can be clearly distinguished) data for April and May of 2001 in Massachusetts to establish when it was dark statewide in Massachusetts using data retrieved from www.sunrisesunset.com on August 1, 2005. For instance, between April 5 and April 12, 2001, the night statewide start and end times were 8:00 p.m. and 4:00 a.m. Between May 14 and May 31, 2001, the night statewide start and end times were 9:00 p.m. and 3:00 a.m.

4. This means that the individual or level‐one cases are nested in specific level‐two zip codes, making the errors correlated and the standard errors biased downward (Guo & Zhao, 2000, p. 444). We therefore corrected for nesting using the cluster command in STATA (Stata Press, 1997, pp. 349–350); also see Messner, Baller, & Zevenbergen, 2005, p. 643).

5. Police officers cannot round up because it is illegal. They also do not need to because there are more than enough high rate speeders to go around (Durose et al., 2007).