The experiment was conducted at the North Carolina Center for Automotive Research NCCAR (NCCAR) in Garysburg, NC, two hours away from Duke University. This professional race track facility enables us to control the traffic conditions without any random passing cars or pedestrians. To use this facility, we had to work with the availability of the track. Our data collection team had 8 people and all need to be available the whole time. We also need to check the availability of participants. It was not worth the cost to make the trip with less than three participants signing up for each day. We cannot collect data when the weather was rainy or two windy.
Because the experiment site was so far away from our lab, we first tried to recruit participants from the local community by sending hundreds of recruitment letters to nearby organizations, including churches, grocery stores, police department, fire department, community colleges, etc. However, we had a very low response from people. With the permission from Walmart managers, our team spent two evenings talking to random customers about our research inside the store and at the entrance of the store. We had some luck getting people from Walmart, but that was still not enough.
Then we were suggested to recruit participants from Duke University. Due to the long distance, we offered rides to participants. They had to leave with us at 7 am or 8 am in the morning and return around 7 pm in the evening. The compensation was $25. We had to have at least three participants on one day to make the trip. We asked our friends to spread the word. Surprisingly, we got some participants from NC State and UNC Chapel Hill. In other words, the project involved three universities, with participants from four distant cities with a relatively low compensation.
On the night before the last day of data collection, we had great difficulty finding the third participant to make the trip the next day. I had to make a decision whether to cancel the trip and reschedule the two people who has already signed up. Right before we gave up, someone agreed to go. On the next morning, when I was driving to the experiment site, another driver called me that one of the students changed his mind and did not want to go that morning, meaning we would need to make one more trip to just collect data for one extra person. Luckily, the director of NCCAR, Sam, helped us find another person to make up the vacancy so that we finished the data collection that day.
Other incidents and difficulties also happened during the experiment.
- On good weather days, our outdoor experiment was conducted under the direct sun, at a temperature of 95F-108F. Some of us were under the sun the whole time.
- The AC of our lab van broke once on our way to the experiment site.
- One evening when we finished data collection for that day, we did not take down the canopies to save setting up time, then it rained and the wind tore the canopies into pieces over the night.
What a great memory!