Table 1

Multivariate analysis of local factors affecting travel speed by motorised vehicles (Poisson linear mixed models, with individual track as random intercept)

Estimate*95% CI
Intercept (km/hour)59.9858.15 to 61.86
Type of road
 National road (paved)(Ref)
 Tertiary road (non-paved)0.450.45 to 0.45
 Unclassified (non-paved)0.460.45 to 0.46
Type of vehicle
 Car/ambulance(Ref)
 Motorcycle1.151.13 to 1.17
Residential area
 No(Ref)
 Yes0.670.67 to 0.67
Bridge
 No(Ref)
 Yes0.700.69 to 0.7
Distance since trip started
 Within 2 km(Ref)
 Over 2 km1.181.18 to 1.19
Slope (%, log10)0.680.68 to 0.68
Rainfall (mm, log10)0.490.47 to 0.5
  • *Model coefficients and CIs are exponentiated to reflect incidence rate ratio (relative change in average speed per unit change in the explanatory variable), except for the intercept which reflects absolute value in kilometre per hour.