Table 2. Multivariable linear models for actual transport time (n = 24,133).

Variable	Coefficient	95% Confidence interval
Street network estimated time <8.8 min
Street network estimated time	2.59	2.58 to–2.61
Lights and sirens	-0.76	-0.83 to -0.69
Rush hour	0.17	0.12 to 0.22
Daylight	0.14	0.10 to 0.18
Street network estimated time ≥8.8 min
Street network estimated time	1.07	1.03 to 1.12
Lights and sirens	-0.40	-0.44 to -0.36
Rush hour	0.16	0.13 to 0.19
Daylight	0.13	0.11 to 0.15
Constant	9.63	9.09 to 10.2

Separate models were used for street network estimated transport times shorter or longer than 8.8 minutes, with the inclusion of a constant in the model for the longer transports. Each term in the model was multiplied by the street network estimated time to account for the increasing effect of each term on transport time. The equation for transports ≥8.8 minutes was Actual transport time = 9.63 + 1.07 * Street network estimated time − 0.40 * Lights and sirens * Street network estimated time + 0.16 * Rush hour * Street network estimated time + 0.13 * Daylight * Street network estimated time.