This page lists the studies behind our guides, plus our own analysis of TxDOT crash data for Fort Worth and the surrounding area.
Whiplash & neck
About half of people with whiplash still have neck pain a year later Verified source
Roughly 50% of people with whiplash-associated disorders still reported neck pain one year after the crash. An international expert task force reviewed 47 good-quality studies of people hurt in car crashes. People who started with worse pain, or who felt down or afraid to move, tended to heal more slowly. The authors also note that 20–40% of all adults report some neck pain in any given month.
"approximately 50% of those with WAD will report neck pain symptoms 1 year after their injuries"
Carroll LJ et al., Bone and Joint Decade 2000–2010 Neck Pain Task Force. Spine, 2008 · Evidence: Review of 47 good-quality studies · Source
Volunteers got neck pain and headaches in bumps as slow as 2.5–5 mph Verified source
About 29% of volunteers had whiplash symptoms after a 2.5 mph speed change, and 38% after a 5 mph speed change. 42 volunteers sat in cars that were bumped from behind at very low speeds. About 3 in 10 got neck pain or headaches at the slowest speed, and almost 4 in 10 at the next speed. Doctors could measure the problems on exam. The speeds are the struck car’s change in speed, not how fast anyone was driving.
"Approximately 29% and 38% of the subjects exposed to the 4 km/h and 8 km/h speed changes, respectively, experienced WAD symptoms."
Brault JR et al. Archives of Physical Medicine and Rehabilitation, 1998 · Evidence: Small lab study (42 volunteers) · Source
A small study found no injury signs in low-speed rear impacts Verified source
Researchers found no injury signs on exam or MRI in 19 volunteers rear-ended at 5.4–8.8 mph, except one man with 10 weeks of stiffness. This study disagrees with Brault 1998. Volunteers were checked with physical exams, motion analysis and MRI scans after low-speed rear impacts.
Castro WH et al. European Spine Journal, 1997 · Evidence: Small lab study (19 volunteers) · Source
Review: neck strain happens in low-speed crashes, worse injury is rare Verified source
Neck pain and strain did occur in low-speed rear impacts, but injury beyond a neck strain was very unlikely at those speeds. The authors combined 51 volunteer studies with real-world crash data. They agree that neck strain and pain happen at low speed. They disagree with Brault on how serious those injuries get.
Cormier J et al. Spine, 2018 · Evidence: Review of 51 volunteer studies (1,984 test crashes) · Source
The Quebec Task Force whiplash grades (0 to IV) Verified source
This report created the standard scale doctors use to grade whiplash, from Grade 0 (no complaints) to Grade IV (fracture or dislocation). Grade II means neck pain plus physical signs such as stiffness or tender spots.
Spitzer WO et al., Quebec Task Force on Whiplash-Associated Disorders. Spine, 1995 · Evidence: Expert task force (foundational, older) · Source
Better-rated head restraints and neck injury claims Being re-checked
Cars with better-rated seats and head restraints had fewer neck-injury claims after rear-end crashes. Exact numbers are being re-checked before we quote them.
IIHS. Traffic Injury Prevention, 2016 · Evidence: Large real-world insurance claims data · Source
Seat ratings and real-world neck injury rates Being re-checked
Seats rated "good" for protecting the neck were tied to fewer neck injuries than seats rated "poor." Exact numbers are being re-checked.
Farmer CM et al. Traffic Injury Prevention, 2008 · Evidence: Real-world claims data · Source
The Canadian C-Spine Rule: why the ER may not X-ray your neck Being re-checked
ER doctors use this checklist to decide who needs a neck X-ray. Neck pain that starts later counts as a low-risk sign for a fracture. Low risk of a fracture is not the same as no injury. If pain develops after the ER visit, follow up with a provider.
Stiell IG et al. JAMA, 2001 · Evidence: Large validated clinical rule · Source
Headache & other body areas
Most people with whiplash get headaches in the first week Verified source
About 60% of people with whiplash had headaches within 7 days. At 12 months, 38% still had headaches and 38% still had neck pain. Researchers pooled 27 studies. Results varied a lot between studies, so the authors call for clearer definitions of whiplash.
Al-Khazali HM et al. Pain, 2020 · Evidence: Review and meta-analysis (27 studies pooled) · Source
Pain after whiplash: a controlled cohort study Being re-checked
A study that followed people with whiplash and compared them with a control group. Numbers are being re-checked.
J Neurol Neurosurg Psychiatry, 1999 · Evidence: Prospective cohort · Source
Whiplash in Greece: symptoms faded quickly (a counterpoint) Being re-checked
In this lower-claim setting, shoulder pain was common at first and faded within months. We include it for balance. Numbers are being re-checked.
Clinical and Experimental Rheumatology · Evidence: Prospective cohort · Source
Course of whiplash symptoms in Sweden over 6 months Being re-checked
A 6-month follow-up of symptoms after whiplash. Numbers are being re-checked.
Journal of Rheumatology, 2010 · Evidence: Cohort study · Source
Chronic headache after whiplash injury Being re-checked
A study of how often whiplash leads to long-lasting headaches. Numbers are being re-checked.
Cephalalgia, 2010 · Evidence: Cohort study · Source
Head injury & concussion
A rear-end crash strained the brain like a concussion-level football hit Verified source
In one rear-end crash, the head wrapped over the head restraint and the brain was strained about as much as in a football hit known to cause concussions. Researchers fed real rear-end crash-test data into a computer model of the brain. Concussion symptoms after a rear-end crash can be real, not "just whiplash."
"One crash, in which the head wrapped onto the top of the head restraint, generated brain strains similar to a 9.3-m/s rear football helmet impact, a level previously associated with concussion."
Elkin BS, Elliott JM, Siegmund GP. Journal of Orthopaedic & Sports Physical Therapy, 2016 · Evidence: Computer model built on real crash-test data · Source
Head restraint position changes how hard your head is thrown Verified source
In low-speed rear-end test crashes, the car’s speed change and how far the head restraint sat from the head mattered most for how hard the head and neck moved. Seat and head restraint setup matters, even at low speed.
Siegmund GP et al. (PubMed 10384232) · Evidence: Lab study with human volunteers · Source
75% of people with a crash brain injury still had several symptoms at 6 weeks Verified source
Six weeks after the crash, 75% reported more than 3 symptoms, and symptoms were still common a year later. Researchers followed 1,716 people in Saskatchewan, Canada, who had a mild traumatic brain injury from a car crash.
Hartvigsen J, Boyle E, Cassidy JD, Carroll LJ. Archives of Physical Medicine and Rehabilitation, 2014 · Evidence: Large population-based study (1,716 people) · Source
Recovery after mild brain injury at U.S. trauma centers (TRACK-TBI) Being re-checked
Many people with a "mild" brain injury were not fully back to normal life a year later. Exact percentages are being re-checked.
Nelson LD et al. JAMA Neurology, 2019 · Evidence: Large multi-center study · Source
Crash-test dummy studies: low calculated risk is not no risk Verified source
Two dummy studies measured head motion in low- to moderate-speed crashes and reported a low calculated concussion risk. The 2025 paper found higher risk in a test where the head hit another occupant. They used a single average-male dummy, properly belted, with head restraints. Lab dummies can’t report symptoms, and real people vary in size, seating position and head-restraint setup. Low risk is not no risk.
SAE 2019-01-1218 and SAE 2025-01-5041 · Evidence: Crash-test dummy studies · Source
Emotional effects
About 1 in 5 crash survivors develop PTSD Verified source
Overall PTSD prevalence after road traffic crashes was 20.3%. It was 29.4% one month after the crash and 18.8% at three months. PTSD means lasting fear, flashbacks or nightmares. It was most common in the first month and eased somewhat by month three.
Systematic review and meta-analysis of 82 studies, 2025 · Evidence: Review of 82 studies · Source
A second review found PTSD in about 26% of crash survivors Verified source
The pooled frequency of PTSD was 26%. A separate meta-analysis that reached a similar conclusion.
Transportation Research Interdisciplinary Perspectives, 2025 · Evidence: Review of 69 studies (16,977 people) · Source
PTSD rates after crashes range widely between studies Verified source
Pooled PTSD prevalence was 22.25%, with individual studies ranging from 6.3% to 58.3%. Rates vary a lot depending on who was studied and how.
Lin W et al. Medicine, 2018 · Evidence: Meta-analysis · Source
Fear of driving after a crash can last months Being re-checked
Many crash survivors become afraid to drive or ride in cars, and for some it lasts at least 6 months. Exact percentages are being re-checked.
Ehring T et al. Journal of Consulting and Clinical Psychology, 2008 · Evidence: Prospective study · Source
Travel phobia after crashes: a cross-sectional study Being re-checked
A study of fear of travel among crash survivors. Numbers are being re-checked.
Ehring T et al. Behaviour Research and Therapy, 2006 · Evidence: Cross-sectional study · Source
Mental health recovery after road traffic injury in Europe Being re-checked
A study of depression and recovery after road injuries. Numbers are being re-checked.
PMC11527739, 2024 · Evidence: Cohort study · Source
Predicting psychological outcomes one year after a crash Being re-checked
A study of which crash survivors still had psychological problems a year later. Numbers are being re-checked.
Mayou R et al. American Journal of Psychiatry, 2001 · Evidence: Prospective study · Source
Treatment & early care
Active, movement-based care beat rest and a soft collar Verified source
Crash patients who got active, movement-based care had less pain and less sick leave than patients told to rest and wear a soft collar. 97 people with whiplash from car crashes were followed for 3 years. Active care reduced pain and sick leave. A 2-week delay did not change most results, but at 3 years only the group that started active care within 96 hours had neck motion similar to people who were never in a crash.
Rosenfeld M et al. Spine, 2003 · Evidence: Randomized trial (97 patients, 3-year follow-up) · Source
An earlier trial of active treatment for whiplash Being re-checked
An earlier trial by the same team compared active treatment with standard advice. Numbers are being re-checked before we quote them.
Rosenfeld M et al. Spine, 2000 · Evidence: Randomized trial · Source
Clinical practice guideline for neck pain and whiplash Being re-checked
A guideline for chiropractors and other providers that recommends education, exercise, manual therapy and staying active for recent whiplash and neck pain. Wording is being re-checked against the guideline text.
Bussières AE et al. Journal of Manipulative and Physiological Therapeutics, 2016 · Evidence: Clinical practice guideline · Source
Honest note: no single whiplash treatment is proven best Verified source
An older Cochrane review could not find clear proof that any one hands-on or exercise treatment works best for whiplash. The studies were small and mixed. That is a reason to choose a provider who explains your plan and tracks your progress.
Verhagen AP et al. Cochrane review, Conservative treatments for whiplash · Evidence: Cochrane systematic review · Source
Active care did better than passive care for recent whiplash Verified source
Active care (movement and exercise) reduced pain more than passive care at 6 months and at 1–3 years. The authors rated the evidence as low quality, and they found no clear difference between starting in the first few days or after about two weeks.
Wiangkham T et al. PLOS One, 2015 · Evidence: Review and meta-analysis (15 trials, 1,676 people) · Source
Neck Pain Task Force: education, exercise and mobilization Being re-checked
For whiplash, education, exercise and mobilization were more likely to help than usual care or passive treatments. Wording is being re-checked.
Hurwitz EL et al. Spine, 2008 · Evidence: Task force review · Source
Manipulation and mobilisation for neck disorders Being re-checked
Manipulation and mobilization gave similar short-term results, and high-quality evidence is limited. Wording is being re-checked.
Gross A et al. Cochrane review · Evidence: Cochrane systematic review · Source
U.S. crash statistics
2.4 million people were injured in U.S. crashes in 2023 Verified source
An estimated 2,442,581 people were injured and 40,901 were killed in U.S. traffic crashes in 2023. National totals from the federal traffic safety agency.
NHTSA, Traffic Safety Facts 2023 (DOT HS 813 762) · Evidence: Government data · Source
Crashes cost the U.S. $340 billion in one year Verified source
The total economic cost of motor vehicle crashes in 2019 was $340 billion, or $1,035 for every person in the U.S. This includes medical costs, lost work, property damage and more.
NHTSA, Economic and Societal Impact of Motor Vehicle Crashes, 2019 (Revised) · Evidence: Government data · Source
People not in the crash pay most of its cost Verified source
Those not directly involved in crashes pay for roughly three-quarters of all crash costs. Through taxes, insurance premiums and traffic delays.
NHTSA press release on 2019 crash costs · Evidence: Government data · Source
Distracted driving in 2023 Being re-checked
National counts of people killed and injured in distraction-affected crashes. Numbers are being re-checked.
NHTSA Research Note, DOT HS 813 703 · Evidence: Government data · Source
About 3.8 million ER visits a year for crash injuries Verified source
Americans made about 3.8 million emergency department visits a year for motor vehicle crash injuries in 2019–2020, and the South had the highest rate. That is 11.6 visits per 1,000 people nationally and 15.0 per 1,000 in the South, which includes Texas.
CDC/NCHS Data Brief 466, 2023 · Evidence: Government data · Source
AAA Foundation 2023 Traffic Safety Culture Index Being re-checked
A national survey of drivers’ attitudes and risky behaviors. Numbers are being re-checked.
AAA Foundation for Traffic Safety · Evidence: National survey · Source
Texas & local crash statistics
In Texas, someone is injured in a crash every 2 minutes 5 seconds Verified source
In 2024, 251,977 people were injured and 4,150 were killed on Texas roads. There was not a single day without a traffic death. A reportable crash happened every 57 seconds. 380 people died in crashes involving distracted driving. 45.34% of those killed were reported as not wearing a seat belt.
TxDOT, Texas Motor Vehicle Traffic Crash Facts, Calendar Year 2024 · Evidence: Government data · Source
Tarrant County had 28,074 crashes and 201 deaths in 2024 Verified source
Tarrant County recorded 28,074 crashes, 189 fatal crashes and 201 deaths in 2024. Hood County recorded 842 crashes and 10 deaths. County totals from TxDOT’s annual crash report.
TxDOT, Crashes and Injuries by County, 2024 · Evidence: Government data · Source
Tarrant County Public Health data brief on motor vehicle crashes Being re-checked
A county public health summary of crash injuries. Numbers are being re-checked.
Tarrant County Public Health, June 2025 · Evidence: Local government data · Source
TxDOT crashes and injuries by city, 2024 Being re-checked
City-level crash totals for Texas cities and towns. City rows are being pulled.
TxDOT 2024 crash statistics archive · Evidence: Government data · Source
Insurance & lawyers
About 1 in 7 Texas drivers had no insurance in 2023 Verified source
14.5% of Texas drivers were uninsured in 2023. Nationally, 15.4% of motorists, more than one in seven, were uninsured. Your own uninsured/underinsured motorist (UM/UIM) coverage is what protects you then.
Insurance Research Council via Insurance Information Institute, 2025 · Evidence: Industry estimate · Source
One in three U.S. drivers was uninsured or underinsured Verified source
One in three drivers (33.4%) were either uninsured or underinsured in 2023. Underinsured means their coverage may be too small to pay for your injuries.
Insurance Research Council press release, 2025 · Evidence: Industry estimate · Source
The insurer-funded "lawyers net less" study (2018) Verified source
Claimants without attorneys received $1.17 per dollar of economic loss; represented claimants netted $0.78 after paying attorneys. The IRC is affiliated with the insurance industry, and represented claims tend to be more serious, so the two groups are not directly comparable. Median time to final payment was 375 days with an attorney.
Insurance Research Council, Countrywide Patterns in Auto Injury Insurance Claims, 2018 · Evidence: Industry closed-claim data · Source
IRC: Attorney Involvement in Auto Injury Claims (2014) Verified source
An industry report on attorney involvement in auto injury claims. Its findings are not publicly available. Listed for completeness.
Insurance Research Council, 2014 · Evidence: Industry report (findings not public) · Source
Last reviewed October 31, 2026. Medical review: pending. Sources are linked in each section and collected on our research library.