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• Enhanced Night Visibility Series, Volume VIII: Phase II—Study 6: Detection of Pavement Markings During Nighttime Driving in Clear Weather

Enhanced Night Visibility Series, Volume VIII: Phase II—Study 6: Detection of Pavement Markings During Nighttime Driving in Clear Weather

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CHAPTER 3—RESULTS

To measure the effect of pavement marking material and VES on pavement marking detection, data on two measures were collected. The first measure was the beginning detection distance, defined as the point where participants indicated first seeing the pavement markings in each section. The second measure was the ending detection distance, when the participants indicated seeing the end of the pavement marking in each section. A series of ANOVAs were conducted to look at the main effects and interactions of pavement marking material, VES, and age for both the beginning and the ending detection distances.

Table 5 represents the results of the ANOVA of the beginning detection distance for VES and pavement marking material. The main effects of VES and pavement marking as well as their interactions were significant (p < 0.05). The post hoc results for the significant main effects and interactions were graphed (figure 11 through figure 14). Means with the same letter (i.e., SNK grouping) are not significantly different.

Figure 11 shows the SNK results on beginning detection distance for each VES. The HLB configurations (i.e., HLB, hybrid UV–A + HLB, three UV–A + HLB, and five UV–A + HLB) and HOH provided the longest beginning detection distances, and they were significantly different from the HID configurations, the HHB, and HLB–LP. Appendix I shows these results side-by-side with results for the ending distances by VES.

Figure 12 shows the SNK results on beginning detection distance for each pavement marking material. The fluorescent paint was statistically different from the fluorescent thermoplastic and the liquid system, and it provided the lowest beginning detection distance of the three.

Figure 13 shows the interaction between pavement marking and VES for beginning detection distance. The fluorescent paint, the thermoplastic, and the liquid system appeared to perform comparably in conjunction with HLB, HLB with UV–A, and HOH. The beginning detection distance for the fluorescent paint diminished compared to the thermoplastic and liquid system when viewed with HHB, HLB–LP, and the HID configurations.

A marginal effect was found for age and beginning detection distance. A post hoc SNK (figure 14) indicates that the young age group attained the highest detection distance, which was significantly different from both the middle and older age groups.

Table 6 outlines the results for the ending detection distance. The main effects of VES configuration, pavement marking, and age were significant (p < 0.05). The interaction between VES and pavement marking was also significant (p < 0.05). Figure 15 through figure 18 illustrate the post hoc results for the significant main effects and interactions.

Figure 15 shows the SNK results on ending detection distance for each VES. For this evaluation, the HLB configurations and HOH provided the highest ending detection distances, and the results were significantly different from those of the HID configurations, HHB, and HLB–LP. Appendix I shows these results side-by-side with results for the beginning distances by VES.

Figure 16 shows the SNK results on ending detection distance for each pavement marking material. For this evaluation, the liquid system and fluorescent thermoplastic were the most visible, but the fluorescent thermoplastic was not significantly different from the fluorescent paint.

Figure 17 represents the interaction between pavement marking and VES for ending detection distance. Ending detection distances were higher for HLB configurations and HOH in conjunction with all three pavement marking materials. Both the thermoplastic and liquid system had high detection distances with HHB, but the fluorescent paint did not perform as well.

Figure 18 represents the SNK results on ending detection distance for age. Young drivers had significantly longer detection distances compared to the other two age groups.