Summary of Traffic Stops Statistics
Gastonia Police Department
The following report compiles and presents statistical summaries of traffic stops statistics drawn from the NC State Bureau of Investigation database to which each police agency reports their statistics each month. Data in this report cover the period of 2002 through 2020. The data exclude checkpoint stops because such stops are not recorded systematically. The data also include only the driver of the vehicle, excluding any passengers. Passenger information is generally recorded only in the event of an adverse outcome (e.g., search, arrest).
This report provides the following summary statistics:
First is a table providing summary statistics on numbers of stops, searches, contraband hits, and arrests, as well as relevant rates of these outcomes. This is followed by a series of graphics displaying department and officer level data.
| Summary of outcomes | State-wide | GPD |
|---|---|---|
| Stops | 24,980,776 | 113,719 |
| Traffic Safety Stops | 13,365,910 | 56,635 |
| Searches | 763,343 | 6,526 |
| Hits | 280,152 | 3,289 |
| Arrests | 500,040 | 4,256 |
| Arrest From Hit From Search | 105,784 | 1,203 |
| Consent Searches | 346,475 | 3,176 |
| Arrest From Hit From Consent Search | 20,759 | 275 |
| Probable Cause Searches | 264,963 | 1,464 |
| Arrest From Hit From Probable Cause Search | 54,326 | 162 |
| Percent Traffic Safety Stops | 53.50% | 49.80% |
| Search Rate Per Stop | 3.06% | 5.74% |
| Hit Rate Per Search | 33.48% | 45.85% |
| Arrest Rate Per Hit | 38.85% | 37.70% |
| Hit-and-Arrest Rate Per Search | 13.86% | 18.43% |
| Hit-and-Arrest Rate Per Probable Cause Search | 20.50% | 11.07% |
| Hit-and-Arrest Rate Per Consent Search | 5.99% | 8.66% |
| Arrest Rate Per Stop | 2.00% | 3.74% |
| Hit-and-Arrest Rate Per Stop | 0.42% | 1.06% |
Numbers at top of the table show raw values; numbers below are the percentages based on the numbers above.
Figure 1 shows the total number of stops per year from 2002-2020. Numbers range from just below 4,000 (in 2015) to just above 10,000 (in 2002).
Figure 2 shows the total number of traffic stops by race and gender from 2002-2020. For example, in 2002, roughly 38% of total traffic stops were of white males, roughly 18% of stops were of black males, roughly 12% were of black females, and roughly 23% were of white females. White males’ share of those stopped decreased over the timeframe. Black drivers, on the other hand, slightly increased as a proportion of total stops. White females did not experience any major fluctuations.
Figure 3. Percent of stops for “safety” purposes (speeding, stop sign, DUI, unsafe movement)
Figure 3 shows the percentage of traffic stops that are considered safety-related for each respective race and gender grouping, from 2002-2020. Safety-related spots are composed of stops due to speeding, stop sign violations, DWI, and unsafe movement. Stops for violations other than this are classified as non-safety related. These are composed of non-moving violations such as equipment violations and expired tags. For this reason, non-safety-related stops can be considered to be used as informal criminal investigations. Each race and gender grouping follows a similar trend from 2002-2020. White females and white males have a similar percentage of safety-related stops throughout the time period. Black male drivers consistently had the lowest percentage of their stops classified as safety-related. Black females typically had a larger portion of their stops classified as safety-related than black males, but both groups were still stopped for non safety-related reasons more frequently than white drivers over the time period.
Figure 4. Percent of stops resulting in a search, by race-gender category
Figure 4 shows the percent of traffic stops that result in a search for each respective race and gender grouping, from 2002-2020. The Figure indicates that most traffic stops do not result in a search. For all categories except black males, drivers were searched at less than a 10% rate across the time period. Black males were typically searched at higher rates, oftentimes at above 10%, and peaking at above 20% in 2020. White males from 2002 to 2008 were the group with the clear second highest search rate. However, post-2008, their search rate was comparable to female drivers. White and black female drivers experienced similar levels of search rates over the time period. The disparity between black males and all other drivers was most drastic from 2016 to 2020, as the search rate of black males increased and the search rate for other drivers converged. From 2013-2014, search data is missing and therefore is not displayed in the Figure.
Figure 5. Percent of stops resulting in arrest, by race-gender category
Figure 5 shows the percent of traffic stops that result in an arrest for each respective race and gender grouping, from 2002-2020. Across the board, arrest rates range from roughly 1% to 16% for all race and gender categories. Black males are arrested at the highest rate, and white males are arrested at the second highest rate (with the sole exception coming in 2014, when black females were arrested at a marginally higher rate). Females, regardless of race, are arrested at lower rates than males. From 2015-2020, arrest data is missing and therefore is not displayed in the Figure.
Figure 6. Percent of stops resulting in contraband and arrest, by race-gender category
Figure 6 shows the percent of stops that resulted in the discovery of contraband and an arrest for each respective race and gender grouping, from 2002-2020. The rates are very low for each category, never surpassing 5%. Black males had the highest rate of stops leading to contraband and arrest. White males from 2002-2006 had comparable rates of contraband and arrest as black males, but for the latter half of the time period, their rates were more comparable to female drivers.All female drivers have rates of less than 2% across the time period. Overall, for all race and gender categories, traffic stops are overwhelmingly unlikely to result in contraband and arrest. From 2015-2020, arrest data is missing and therefore is not displayed in the Figure.
Figure 7. Black-White Ratio of search rates and arrest rates, for males
Figure 7 compares the search rate and arrest rate of black males and white males from 2002-2020. The search rate ratio is the search rate of black males divided by the search rate of white males, while the arrest rate ratio is the arrest rate of black males divided by the arrest rate of white males. A search rate ratio of 1.0 would indicate that black and white males are both searched in an equal percentage of their respective traffic stops. This similarly applies for the arrest rate ratios. Across the time period, the search rate ratio is consistently above 1. The ratio ranged from 1.2 to 2.6, and has great variation year-to-year. This means that black males are searched much more frequently than white males in most years across the time period. The arrest rate ratio also is consistently above 1. It is typically quite close to the search rate ratio, with the exceptions of 2009-2010, 2012, and 2014, when the two ratios diverged more dramatically. From 2015-2020, arrest data is missing and therefore there is no arrest rate ratio for these years.
Figure 8. Black-White Ratio of search rates and arrest rates, for females
Figure 8 compares the search rate and arrest rate of black females and white females from 2002-2020. The search rate ratio is the search rate of black females divided by the search rate of white females, while the arrest rate ratio is the arrest rate of black females divided by the arrest rate of white females. A search rate ratio of 1.0 would indicate that black and white females are both searched in an equal percentage of their respective traffic stops. Across the time period, the search rate ratio ranges from 0.4 to 1.5. The arrest rate ratio is typically close to the search rate ratio for the given year, generally being slightly higher. The main exceptions occur in 2009 and 2013, when the arrest rate ratio was significantly higher. From 2015-2020, arrest data is missing and therefore there is no arrest rate ratio for these years.
Figure 9. Summary of stops by hour over the week: Stops, percent safety-related, percent ending in citation, search, and arrest
Figure 9 displays the number of traffic stops, the percent of safety related stops, the percentage of drivers receiving a citation, the percentage of drivers searched, and the percentage of drivers arrested across the hours of the week. The Figure indicates that there is not much variation between the days of the week in regard to these measures, and instead shows that the variation is seen within the hours of the day. There are a few noticeable trends throughout the week, however. Stops occur most frequently on Friday and Saturday nights relative to other days at the same time. Search rates spike drastically on early Sunday morning.
Figure 10. Summary of stops by hour over the day: Stops, percent safety-related, percent ending in citation, search, and arrest
Figure 10 displays the number of traffic stops, the percent of safety related stops, and the percent of drivers searched, given a citation, and arrested by hour of day. There are a number of clear trends indicated in the Figure. The frequency of a traffic stop is lowest in the early hours of the morning, decreasing until 6AM. The number of traffic stops then increases until 9AM, at which the frequency is similar until around 7PM. From 7PM to 10PM stops increase, and until midnight stops occur at a higher rate. At midnight, the frequency of stops begins to drop.
The percentages of drivers searched and arrested both have a roughly similar trend across the time of day. Drivers are both searched and arrested at the highest rate in the few hours after midnight, and then these rates of search and arrest decrease dramatically until 7AM. After 7AM, the rate of both search and arrest is at extremely low percentages, and both slowly increase throughout the daytime and into the late night time hours. The arrest rate is extremely variable throughout the day. This is likely due to the limited arrest data as compared to search rate data.
The percentage of drivers receiving a citation follows an opposite trend of search and arrest rates. The rate of citations given is at its lowest from 8PM to 3AM, and then in the following hours steadily increases. The rate is significantly higher during daytime hours as compared to nighttime hours. The percentage of safety-related stops follows this same trend.
Figure 11. Hourly breakdown of percent of stops by race-gender category
Figure 11 displays the share of overall stops represented by the respective race and gender categories by hour of day. The Figure indicates that black males are more likely to be stopped during the nighttime hours directly before and after midnight than they are to be stopped during the daytime. From midnight to 3AM, black males make up about 31% of those that are pulled over, and by 8AM their share of stops decreases to below 15%, and stays at a lower proportion of stops throughout the daytime hours. White males, in contrast, make up a relatively consistent share of the overall traffic stops throughout the day, at around 25%. From 4AM to 6AM, there is however a temporary increase in their proportion of stops. Black females make up a relatively consistent share of traffic stops throughout the day, from roughly 15-20%. White females see a major uptick in their proportion of stops during the daytime hours.
Figure 12. Hourly breakdown of percent of stops related to traffic safety, by race-gender category
Figure 12 displays the percentage of stops that are for safety-related purposes for each race and gender category, by hour of the day. Safety-related purposes refer to traffic stops that are meant to prevent moving violations, and effectively keep the road safe. Stops that are not safety-related are often used for investigatory purposes, in which case the officer is generally seeking to conduct an informal criminal investigation of the driver. As evidenced by the Figure, all race and gender groups have extremely similar rates of safety-related stops throughout the day. Black drivers are typically still stopped in the lowest percentage of safety-related stops, but this disparity is not nearly as pronounced as in other comparable departments. For all groups, safety-related stops are more likely to occur during the daytime hours, and are at their lowest in the hours before and after midnight. There is insufficient stop data for all drivers from 5-6AM, and therefore it is not displayed. Also, there is insufficient stop data for all female drivers at 4AM.
Figure 13. Hourly breakdown of percent of stops resulting in search, by race-gender category
Figure 13 displays the percentage of traffic stops which result in a search for each race and gender category, by hour of the day. During the hours directly after midnight, search rates for all race and gender groups are their highest. Black males, white males, and white females all have relatively comparable search rates during these hours. Black females see a sharp increase at 3AM but are generally searched at lower rates during this portion of the day. During daytime hours, black males are significantly more likely to be searched than other race and gender categories. Throughout the entire day, white males are searched at rates comparable to female drivers. The Figure also indicates that a majority of stops do not result in a search regardless of race and gender category or time of day.
Figure 14. Hourly breakdown of percent of stops resulting in arrest, by race-gender category
Figure 14 displays the percentage of traffic stops which result in an arrest for each race and gender category, by hour of the day. Arrest rates throughout the entire day are extremely low. At many points, the arrest rate is zero, as no arrests of that specific race and gender category have been recorded. Black males do see a single sharp increase at 6AM, with 3% of stops resulting in arrest. There are no other instances of an arrest rate over 2% for any of the race and gender categories. Rates do increase during the nighttime hour, but this increase is minimal.
Figure 15. Number of stops by officer
Figure 15 displays the distribution of number of stops by officer across the 2002-2020 time period. All officers displayed have over 100 traffic stops. 149 of the 220 officers included in the data have less than 500 traffic stops.
Figure 16. Percent black of drivers pulled over by officer
Figure 16 displays the percentage of stopped drivers that are black for individual officers, from 2002-2020. The distribution includes officers with greater than 100 traffic stops. For the median officer, 35.7% of stops are of black drivers, while black people only make up 29.2% of the population in the city. This means that a majority of officers are stopping black drivers at a rate disproportionate to their share of the population. This disparity between stop behavior and population data is often greater, with black drivers composing more than 45% of stops for a significant portion of officers. At the far right, the Figure shows that there are 31 officers whose mix of drivers stopped is more than 45% black.
Figure 17. Officer search rates by race
Figure 17 displays the search rates of individual officers for the given race and gender category. The criteria for an officer’s inclusion is 100 or more traffic stops, as well as at least 50 stops of the specified race and gender category, from 2002-2020. In the first graph, the median officer has a search rate of 8.59%, meaning that black male drivers are searched in 8.59% of traffic stops. Many officers have search rates that are higher than this median value, meaning that searches occur more often for certain officers in traffic stops involving black males. For white male drivers, the median officer has a search rate of 4.42%. This indicates that the median officer in Gastonia is searching black males at a higher rate than they are searching white males.
Figure 18. Black-White Ratio of search rates by officer, for males
Figure 18 displays the distribution of black-white male search rate ratios across the officers which meet the criteria. The criteria for an officer’s inclusion is 50 traffic stops of both white males and black males, from 2002-2020. The “Black-white male search rate ratio” can be interpreted as an officer’s search rate of black male drivers divided by their search rate of white male drivers. An racially equitable outcome would therefore be 1, meaning that black and white male drivers are searched in an equal percentage of traffic stops. The median officer instead has a search rate ratio of 1.57, meaning that the median officer searches black male drivers at a higher rate than white male drivers. A significant number of officers have search-rate ratios that are much higher than the median.
Figure 19. Search rate versus hit rate by officer
Figure 19 presents the hit rates and search rates of individual officers who meet the criteria. As evidenced by the low correlation, there is great variability in both the propensity of individual officers to search drivers and their success in finding contraband. One might expect that when officers have a high search rate but a low hit rate, that their supervisors would advise them to adjust their search rate in order to avoid so many fruitless searches. Similarly, for officers with low search rates but high hit rates, one might expect supervisors to instruct them to conduct more searches because they are being too cautious. Such a learning process would generate relative consistent hit rates; where officers are too high, they would be advised to do more searches, and where too low, to conduct fewer. The Figure shows clearly that this is not happening. Search and hit rates range from low to high, with a very low correlation between the two. Certain officers search drivers at extremely high rates but have very low hit rates, meaning that their threshold of suspicion is likely too low. Other officers search at a much lower rate and have very high hit rates, showing that their threshold of suspicion may be too high. Overall, the Figure shows that officers are not gravitating towards a single common range of hit rates. This suggests that the department does not seem to hold its officers to a common standard of search rate success. Rather, each officer decides for him or herself how aggressive to be in searching, with virtually no guarantee that more searches will lead to lower hit rates, or that fewer searches will be targeted on those most likely to have contraband.