Table 4.

Impact of weather factors on trip duration in the San Francisco Bay Area.

			Weekday				Weekend
Season	Variable	All trips	All weekday	Commute	Transit (commute)	Non-commute
All	Temperature (°C)	1.002 *	1.001 *		1.001 *	1.002 *	1.001
	Humidity (%)		1.000 *		1.000 *	1.000 *	0.999 *
	Wind speed (km/h)
	Precipitation (mm/h)
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover	1.015 *
	Heavy cloud cover	0.988 *	0.990 *	0.983 *	0.990 *		1.014
	Fog	1.100 *	1.097 *		1.097 *	1.134 *	1.070
Winter	Temperature (°C)	1.001 *	1.001
	Humidity (%)	0.999 *	0.999 *	0.999	0.999 *	0.999 *	0.999 *
	Wind Speed (km/h)
	Precipitation (mm/h)
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover	1.035 *	1.025 *			1.029 *
	Heavy cloud cover	0.986 *	0.987	0.972
	Fog	1.105 *	1.09 *		1.089	1.147 *	1.104 *
Spring	Temperature (°C)	1.010 *	1.004 *			1.007
	Humidity (%)	1.001 *	1.001			1.001
	Wind speed (km/h)
	Precipitation (mm/h)
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover	1.021
	Heavy cloud cover	0.980 *
	Fog
Summer	Temperature (°C)	0.991 *
	Humidity (%)	0.997 *	0.998
	Wind speed (km/h)	1.003 *	1.003 *		1.004 *	1.003 *
	Precipitation (mm/h)			2.239
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover	1.054 *	1.035		1.064	1.041
	Heavy cloud cover		0.984		0.955		1.048 *
	Fog
Autumn	Temperature (°C)
	Humidity (%)	0.999 *	1.000
	Wind speed (km/h)	1.001 *	1.001 *
	Precipitation (mm/h)		1.003
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover		0.998
	Heavy cloud cover	0.985 *	0.986				1.027 *
	Fog		1.089

Note: Coefficients indicated with no asterisk are significant at α = 0.05 and coefficients indicated with an asterisk (*) are significant at α = 0.01. Variables corresponding to all insignificant coefficients were omitted during the model estimation process.