REQUIREMENTS: Compatible with iPad.
Requires iOS 3.2 or later.
The MomentumWithTimeDistance Application is a 360˚ conservation of linear momentum program that allows the collision investigator to determine vehicle velocities in two vehicle collisions utilizing the conservation of linear momentum based on:
• Vehicle Weights (masses)
• Approach and Departure Headings and
• Any combination of 2 of the 4 involved velocities.
Unlike most traditional momentum programs, the momentum 360 application does not limit the accident investigator to using only the post impact velocities when determining speeds. Instead, iPad Momentum Application allows the investigator to use any combination of the 2 impact and post impact velocities in order to solve the remaining 2 unknown velocities.
The approach and departure angles may be entered in either a clockwise or counterclockwise direction, and there is no requirement that any of the angles have to be set to 0 degrees.
All of the data may be entered directly into the application through the use of text boxes. However, all of the entered values may be adjusted up and down through the use of a series of sliders. This permits the investigator to quickly determine any sensitivity issues that may be associated with the selected data simply by moving the slider, causing the calculated results to change instantly along with the selected data.
To activate the slider, the button adjacent to the data is selected, which in-turn will highlight the selected data in red. The slider that appears below the selected data element will control its value.
The main data screen displays the momentum results (impact and post impact speeds/velocities), the change in velocities of both vehicles as well as their respective principal direction of force. Additionally, each vehicle’s change in direction, impact kinetic energy and post impact kinetic energy are calculated and displayed along wither their closing and separation velocities and the collision restitution.
If there is evidence of pre-impact braking by one of the involved vehicles, its skid distance, coefficient of friction, braking percentage and roadway grade may be entered for up to three surfaces. Once pre-impact data has been entered the time the vehicle lost in the skid, pre impact speed/velocity and time and distance from impact at the driver’s point of perception will be determined and displayed.
There are two additional screens. The first, or calculations screen, displays all of the calculations from the results on the main page in a step-by-step or line-by-line manner. These line-by-line calculations may emailed, along with the results on the main screen, so they may be copied and pasted into a report or other document.
When there has been pre impact speed loss data entered for one of the vehicles, the third screen permits the investigator to conduct an in-depth time distance analysis. With a few additional data elements, a “What-if” analysis may be conducted to determine if the collision would have occurred had the through or favored vehicle been traveling at the posted speed limit. If the collision would have been avoided, the distance the intruding vehicle would have cleared the area of impact is determined, while also determining if it was necessary for the driver of the through vehicle to take any evasive actions to avoid the collision.
Finally, if there is a traffic signal involved and the intruding vehicle driver was reacting to the green light while the through vehicle ran the red light, then the program will determine how far from the stop bar, in both time and distance, the vehicle was when the light turned red.
As with the other two screens the result from this screen may be emailed so the results may be copied or pasted into report or other document.
Corrected email results for the pre impact velocity calculations and change in direction. Change in direction was displaying change in velocity value. The value for the pre impact velocity was displaying the results for the Post Impact Velocity. (Speed results were correct.)
Added text field for perception reaction time allowing the perception reaction time to be entered directly or through the use of the slider.