Services
Document a loss
Support a claim
For carriers and employers
Service areas
Middle Tennessee
- Nashville
- Clarksville
- Murfreesboro
- Franklin
- Hendersonville
- Smyrna
- Spring Hill
- Gallatin
- Lebanon
- Columbia
- Brentwood
- Mount Juliet
- La Vergne
- Cookeville
East Tennessee
West Tennessee
Collision Scene Measurements for Reconstruction and Claims
Field measurement of collision scenes using baseline and triangulation methods tied to permanent reference points. For adjusters, attorneys and reconstruction experts who need distances they can plot, check and defend rather than estimates read off a photograph.
- Coverage
- 95 of 95 counties
- Dispatch
- 24 / 7 / 365
- Metro response
- Under 60 min avg.
- Statewide
- 4-hour guarantee
What this service covers
A photograph compresses distance. Two marks that look adjacent in an image may be forty feet apart on the pavement, and nobody can recover the true figure afterward. Scene measurement fixes each item of evidence by distance from known points, so the scene can be drawn to scale on paper or in software. The work is slow and methodical, and it is the part of scene documentation most often skipped when a crash is cleared quickly.
Two methods cover most roadways. With a baseline, a straight reference line is established along a curb or road edge from a fixed starting point, and each item is located by its distance along the line and its offset from it. With triangulation, each item is located by its distance from two fixed reference points. The investigator selects the method that suits the site, records which was used, and notes every reading with its units.
Situations that call for measured distances
- A police diagram marked not to scale is the only drawing of the scene and the parties disagree about distances.
- A reconstruction expert needs point locations to build a scale diagram but will not be traveling to Tennessee.
- An adjuster must compare a driver's stated stopping distance against the length of roadway physically available before the impact area.
- A lane width, shoulder width or median opening is central to whether a claimed maneuver was physically possible.
- Defense counsel wants measurements taken independently to check figures already offered by the opposing party's consultant.
What is measured and how it is recorded
- Baseline and zero point
- The reference line and its starting point are described, photographed and tied to a permanent object, so another person can re-establish the same line later.
- Triangulated evidence points
- Items on curves, in open intersections or off the roadway are located by two distances from separate fixed points, each written with the points it was taken from.
- Roadway cross-section
- Lane, shoulder, median and turn-lane widths are measured at stated stations, with the position of edge lines, center lines and stop bars.
- Grade and cross-slope
- Slope along the direction of travel and across the lanes is recorded at stated points on each approach, because both affect how a vehicle slows and tracks.
- Curve geometry
- On curved segments a chord and middle ordinate are measured at the road edge, which allows an analyst to work out the radius of the curve.
- Check measurements
- Selected distances are measured a second time by a different route between points, giving the analyst a way to gauge the consistency of the data set.
From request to delivered record
- RequestCall dispatch or submit the request form with the location, loss type and urgency.
- DeployDispatch assigns the nearest available licensed field investigator through the statewide network.
- DocumentPhotographs, video, measurements and factual notes are captured once the scene is safe to work.
- PreserveFiles are timestamped, organized and kept in their original form with a record of who captured them.
- ReportThe package is delivered securely to the requesting party, typically the same day.
Reference points decide whether measurements can be reproduced
A measurement is useful only if someone else can find where it was taken from. Reference points are therefore chosen for permanence: the corner of a concrete drain inlet, a numbered utility pole, a bridge joint, the end of a curb return. Painted lines, posts that can be reset and temporary construction features are avoided or noted as secondary. Each point is photographed close and wide, described in the notes, and given a label used throughout the measurement table.
Roadways change. Intersections are restriped, shoulders are paved and signals are relocated, sometimes within months of a collision. A measurement set tied to permanent points survives those changes, and it lets a later visitor confirm that the site still matches the record. Where the roadway has been altered between the crash and the visit, the notes say so and identify what appears new, so the analyst does not treat current striping as the layout the drivers encountered.
What measured data lets an analyst establish
With point locations in hand, an analyst can draw the scene to scale and place the vehicles on it. From there the distances that matter become available: how far a vehicle moved between the area of impact and final rest, how long a tire mark ran and at what angle to the lane, how much roadway lay between a point of possible perception and the collision. Grade and curve data qualify those distances. None of this can be recovered from memory or from unscaled images.
The measurement table is delivered with the photographs and field notes, typically the same day, in a format the retaining party's expert can plot. The investigator reports the readings and the method. Delator's personnel have accident reconstruction experience and understand which distances an analyst will look for, but the measurement assignment itself draws no conclusion about speed, reaction or legal fault. Those questions are left to the analysis and to the people deciding the claim.
Delator personnel have accident reconstruction experience. The work product is physical evidence and technical findings; it does not determine legal fault, which remains with the parties, the court or a jury.
Delator Claims Division is not an engineering firm. Whether any analysis is accepted in a proceeding is decided by the court.
Common questions about this service
How accurate are the measurements?
Each reading is recorded with its units, the method used and the points it was taken from, and selected distances are checked by a second measurement. The field notes state conditions that limit precision, such as live traffic preventing access to a lane. No accuracy figure is claimed beyond what the method supports.
Can measurements be taken on an open interstate?
Investigators work from positions that can be occupied safely and lawfully, such as shoulders, medians and overpasses. They do not close lanes or direct traffic. Where an item in a live lane cannot be reached, it is located by photographs with scale references from the shoulder and the limitation is written into the notes.
Do you produce the scale diagram or only the data?
The standard deliverable is the measurement table, reference point descriptions, photographs and field notes, which is what a reconstruction expert normally works from. If you need a drawn scale diagram as well, say so when requesting the assignment so the scope can be confirmed before the visit.
Can you measure a scene after the vehicles and debris are gone?
Yes. Roadway geometry, reference points, gouges and many tire marks remain after clearance, and police paint marks often show where vehicles came to rest. Those are measured as found. The notes distinguish evidence observed on the visit from positions taken from other sources, such as a police photograph you supply.
Available statewide, including
Every Tennessee county is covered. See the deployment map for typical response tiers by county.
Request documentation anywhere in Tennessee
Dispatch is staffed around the clock. For time-sensitive scenes, calling is fastest; the request form works for routine and scheduled assignments.