5,352 CRASHES IN
IOWA, IA
DECEMBER 2015

Of the individuals killed or seriously injured, motorists comprised the largest group, with 21 fatalities and 1,531 injuries. Vulnerable road users also suffered significant harm; 3 pedestrians were killed and 31 were injured. Additionally, 7 cyclists were injured in crashes during this period.

Crash patterns in December 2015 showed a clear peak during the work week, with Thursday being the most frequent day for incidents, recording 1,061 crashes. The evening commute was the most hazardous time of day, as the hour between 5 p.m. and 6 p.m. saw the highest volume with 626 crashes. While incidents occurred around the clock, a majority of crashes (2,563, or 47.9%) happened during daylight hours.

The vast majority of crashes, 76.1% (4,071 incidents), resulted in no injuries. Injury-sustaining crashes, including those with possible, minor, or serious injuries, accounted for 23.5% of the total (1,259 incidents). A small fraction of crashes, 22 in total (0.4%), were fatal. These 22 fatal crashes led to the deaths of 24 individuals, as a single crash can result in multiple fatalities.

Severity is per crash event (most severe injury). 22 fatal crash events resulted in 24 persons killed.

Analysis of contributing factors reveals that environmental and driver behaviors were primary drivers of crashes. The leading reported factor was the presence of an animal on the roadway, cited in 800 crashes (14.9%). Driver errors followed, with 'Followed too close' listed in 478 incidents (8.9%) and 'Driving too fast for conditions' in 475 incidents (8.9%).

A substantial number of crashes occurred in seemingly ideal conditions, with 47.9% (2,563) happening in daylight and 47.6% (2,547) on dry road surfaces. However, adverse winter conditions played a significant role, as 658 crashes occurred in snow and 573 on snow-covered roads. An additional 886 crashes took place on wet road surfaces, and 1,113 incidents happened on lighted roadways after dark.

Among the 10,738 people involved in crashes, individuals in the 26-34 age group were the most represented, with 1,767 people. Analysis of the 9,018 vehicles involved shows a prevalence of domestic brands. Chevrolet was the most frequent make with 1,945 vehicles, followed by Ford with 1,484 and Dodge with 668 vehicles involved in collisions.

The leading major cause attributed to crashes in Iowa during this period was the presence of an animal, cited in 800 incidents. Following this, common driver errors were prominent, including 'Followed too close' which was a factor in 478 crashes, and 'Driving too fast for conditions' noted in 475 crashes. Losing control of the vehicle was also a significant factor, contributing to 367 crashes.

The most common first harmful event was a 'Collision with: Vehicle in traffic,' which occurred in 2,866 crashes. Collisions with animals were the second most frequent event, accounting for 790 incidents. Single-vehicle events were also common, with 'Overturn/rollover' being the first harmful event in 255 crashes and collisions with a ditch in 269 crashes.

Analysis of crash locations shows that more incidents occurred on non-intersection road segments than at intersections. Crashes at 'Non-junction/no special feature' locations accounted for 2,550 incidents. In comparison, traditional 'Four-way intersections' were the site of 1,192 crashes, making them the most common type of junction for collisions.

Passenger cars were the most common vehicle type involved in crashes, accounting for 4,274 of the 9,018 vehicles. Sport utility vehicles were the second most frequent type with 1,960 vehicles, followed by four-tire light trucks and pickups at 1,545. Commercial vehicles also had a notable presence, with 238 tractor/semi-trailers involved in incidents.

A majority of vehicles involved in crashes were in areas with no traffic controls present, accounting for 5,180 vehicles. For crashes where traffic controls were a factor, traffic signals were the most common, with 1,935 vehicles involved in incidents at signalized locations. Stop signs were the next most frequent traffic control device, present for 901 vehicles involved in crashes.

The front of the vehicle was the most common area of impact, recorded as the most damaged area for 2,291 vehicles. This suggests a high prevalence of head-on or front-corner collisions. The rear of the vehicle was the most damaged area in 1,139 cases, which aligns with the high number of rear-end collisions reported.

Driver impairment was suspected or confirmed in 151 crashes, representing 2.8% of all incidents. Alcohol was the most frequently cited substance, involved in 138 of these crashes. Drugs were a factor in 11 crashes, and a combination of alcohol and drugs was noted in 2 incidents.

Crash distribution was concentrated in Iowa's most populous counties. Polk County, home to Des Moines, recorded the highest number of incidents with 934 crashes, representing 17.5% of the statewide total. Scott and Linn counties followed, each reporting 333 crashes, with Black Hawk County recording 244 crashes.

Iowa's major cities saw the highest concentration of crashes within municipal boundaries. Des Moines led with 495 crashes, significantly more than any other city. Following Des Moines were Davenport with 246 crashes, Cedar Rapids with 214, and Sioux City with 213 incidents.

The vast majority of crashes, 5,125 incidents, occurred on paved roadways. However, Iowa's extensive secondary road network was also a factor, with 208 crashes, or 3.9% of the total where surface type was known, taking place on unpaved surfaces like gravel or dirt.

Among crashes where a roadway factor was noted, adverse surface conditions were the leading contributor, cited in 1,047 incidents. This includes wet, icy, or snow-covered roads. A slippery or worn surface was a factor in an additional 54 crashes, while work zone-related roadway issues contributed to 24 incidents.

While most drivers were recorded as 'Apparently normal,' several other conditions were noted as potential factors. Among these, 'Under the influence of alcohol' was the most common, recorded for 168 drivers. Driver fatigue was also a notable factor, with 54 drivers reported as 'Asleep/fatigued,' and 39 drivers were noted as being in an emotional state.

Crash distribution across Iowa's six DOT districts shows a concentration in the state's primary population and traffic corridors. District 1 (Central Iowa/Des Moines) had the highest volume with 1,519 crashes. District 6 (Eastern Iowa/Cedar Rapids) was second with 1,353 crashes, and together these two districts accounted for over half of all incidents.

The majority of crashes resulted in moderate property damage, with 3,964 incidents having an estimated cost between $1,500 and $7,500. A smaller but significant number, 1,170 crashes, fell into the $7,500 to $25,000 range. There were 97 crashes that resulted in severe property damage estimated at over $25,000.

Single-vehicle crashes, categorized as 'Non-collision,' were the most frequent type of incident, accounting for 2,025 crashes or 37.8% of the total. Among multi-vehicle incidents, rear-end collisions were the most common, with 1,236 crashes (23.1%). Broadside collisions were the next most frequent type, occurring in 858 crashes (16.0%).

The most common action for vehicles immediately prior to a crash was 'Movement essentially straight,' recorded for 5,261 vehicles. Actions related to intersections or turning were also frequent, with 776 vehicles turning left and 330 turning right. Additionally, 486 vehicles were stopped in traffic at the time of the collision.

For the 34 pedestrian-involved crashes where an action was recorded, the vast majority of individuals were 'Entering or crossing roadway' at the time of the collision. This action was noted for 30 of the pedestrians involved in crashes.

Of the 10,738 individuals involved in crashes, the overwhelming majority were drivers, accounting for 10,303 people. Passengers made up the next largest group with 393 individuals. The data also includes 34 pedestrians and 7 bicyclists who were involved in collisions.

Across all 10,738 individuals involved in crashes, 24 people sustained fatal injuries and 1,570 suffered some level of injury. This includes 88 serious injuries, 468 minor injuries, and 1,014 possible injuries. The majority of people involved did not have a reported injury.

Based on the limited data available for safety equipment usage, 1,137 occupants were reported to have used a shoulder and lap belt. In contrast, 100 individuals were recorded as using no safety restraint at the time of the crash. Child safety seats of various types were used by 25 occupants.

Two-vehicle collisions were the most common scenario, accounting for 2,981 crashes. Single-vehicle crashes were also very frequent, with 2,060 incidents reported. Multi-vehicle pile-ups involving three or more vehicles were less common, with 267 crashes involving three vehicles and 33 crashes involving four.