Measure intersection delay time - anylogic

Question

Using the Road Traffic Library, I have created a 4-way intersection that is stop-controlled and I need to measure the average delay for each approach. Currently I am using timeMeasureStart and timeMeasureEnd blocks, showing the time taken as the car enters the road/model, until it exits the intersection.
Instead, I want to measure from the time the car slows to 40km/h, until it exits the intersection. Any suggestions?
The initial speed of all cars entering the model is 60 km/hr.

Answer 1

Sure, there is no pre-defined way but this custom approach should work:
make sure your cars are a custom agent type, not the default cars. Lets name it My Car
add a variable myTimeBelow40 into MyCar of type double
check the car speed regularly (every 0.1 sec?!) in an event in MyCar.checkSpeed. Use the getSpeed() function. If it is below 40 KPH, you log the current time into myTimeBelow40
log the departure time of your car: your time since 40 KPH is the difference
Finally, add a statistic across your car population or log your individual car duration into main

Answer 2

#Benjamin thank you for pointing me in the right direction.
Here is my solution, guided by the suggestion. I'm sure it could be refined but in the end it is what worked for me and my limited knowledge of AnyLogic.
For a 4-way intersection, I wanted the delay for each approach, so I created 4 custom car agents, with each populations starting out empty.
In each agent, I had 2 variable blocks - var_Start and var_Slow, an one event block set to Timeout, Cyclic, first read at time(), and proceeding in intervals of 0.1s. In the event action, i specidied the following:
if(getSpeed(KPH) <= 40) {
var_Slow=time();
var_Slow.suspend();
}
In main I used Histogram Data, labeled as dataDelay, and a chart with the mean showing, to see the results. I had one for each intersection.
Back in the car agent, in actions on startup:
var_Start=time();
and on destroy:
if(var_Slow = 0)
main.dataDelay.add(time()-var_Start);
else
main.dataDelay.add(time()-var_Slow);
At the car source block in main, I kept the initial and prefered speed at 60, however if there were cars backed up then new cars were often initiated at a slower speed, sometimes already below 40kph, hence the if,else code on destroy.
I had everything labeled according to its corresponding approach direction, unlike the simplified version I have here.