Study of Excessive Temperatures in Enclosed Vehicles
(PDF version)
Jan Null, CCM ^1,2
June 2003

BACKGROUND
Every year dozens of children tragically die due to hyperthermia (heat stroke) after being left unattended in cars, trucks and vans.  Over the past five years in the United States 160 deaths of this type have been documented  (Kids and Cars and 4 R Kids Sake^TM, 2003).  [For the current year see 2003 Hyperthermia Fatalities (Children in Vehicles)].  Hundreds of other children left in similar situations suffer great bodily harm and these numbers do not include similar consequences to infirm adults or animals.

OBJECTIVE
This study quantifies vehicle temperatures and temperature changes with time under a variety of meteorological circumstances.

STUDY DESIGN
Temperature sensors were placed two types of vehicles on sunny days with ambient temperatures ranging from 70 F (21C) to 100 F (38C).  The initial interior temperature was regulated to equal the ambient temperature.  The vehicles were in full sun but the sensors in the vehicles were not subject to direct sunlight and were not in direct contact with any interior surface.  Except as noted in the results, the trials were conducted in a mid-sized dark blue sedan with medium gray interior and all of the windows were fully closed.  Using wireless temperature sensors the ambient outside and the inside vehicle temperatures were sampled every five minutes for at least one hour.  A secondary vehicle (a white mini-van with light gray interior) was used for some tests.  Neither vehicle had tinted windows.

TRIAL SUMMARY
Between May 16, 2002 and Aug 8, 2002 twenty-one trials were conducted on 15 days.  Table 1 summarizes the ambient and inside vehicle temperatures on the primary test vehicle with the windows fully closed.  Table 2 compares the temperature in the primary test vehicle on three occasions when the windows were fully closed and then when they were “cracked” open approximately 1.5 inches.  Table 3 is a summary of two additional test cases using the primary vehicle and the secondary vehicle.