Hi there, I am trying to create a simulation of motorway and the behaviour of the drivers in NetLogo. I have some questions that I m struggling to solve. Here is my code: globals [ selected-car ;; the currently selected car average-speed ;; average speed of all the cars look-ahead ] turtles-own [ speed ;; the current speed of the car speed-limit ;; the maximum speed of the car (different for all cars) lane ;; the current lane of the car target-lane ;; the desired lane of the car change? ;; true if the car wants to change lanes patience ;; the driver's current patience max-patience ;; the driver's maximum patience ] to setup ca import-drawing "my_road3.png" set-default-shape turtles "car" crt number_of_cars [ setup-cars ] end to setup-cars set color blue set size .9 set lane (random 3) set target-lane (lane + 1) setxy round random-xcor (lane + 1) set heading 90 set speed 0.1 + random 9.9 set speed-limit (((random 11) / 10) + 1) set change? false set max-patience ((random 50) + 10) set patience (max-patience - (random 10)) ;; make sure no two cars are on the same patch loop [ ifelse any? other turtles-here [ fd 1 ] [ stop ] ;if count turtles-here > 1 ; fd 0.1 ;if ; ;ifelse (any? turtles-on neighbors) or (count turtles-here > 1) ;[ ; ifelse (count turtles-here = 1) ; [ if any? turtles-on neighbors ; [ ; if distance min-one-of turtles-on neighbors [distance myself] > 0.9 ; [stop] ; ] ; ] ; [ fd 0.1 ] ;] ;[ stop ] ] end to go drive end to drive ;; first determine average speed of the cars set average-speed ((sum [speed] of turtles) / number_of_cars) ;set-current-plot "Car Speeds" ;set-current-plot-pen "average" ;plot average-speed ;set-current-plot-pen "max" ;plot (max [speed] of turtles) ;set-current-plot-pen "min" ;plot (abs (min [speed] of turtles) ) ;set-current-plot-pen "selected-car" ;plot ([speed] of selected-car) ask turtles [ ifelse (any? turtles-at 1 0) [ set speed ([speed] of (one-of (turtles-at 1 0))) decelerate ] [ ifelse (look-ahead = 2) [ ifelse (any? turtles-at 2 0) [ set speed ([speed] of (one-of turtles-at 2 0)) decelerate ] [ accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] [accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] if (speed < 0.01) [ set speed 0.01 ] if (speed > speed-limit) [ set speed speed-limit ] ifelse (change? = false) [ signal ] [ change-lanes ] ;; Control for making sure no one crashes. ifelse (any? turtles-at 1 0) and (xcor != min-pxcor - .5) [ set speed [speed] of (one-of turtles-at 1 0) ] [ ifelse ((any? turtles-at 2 0) and (speed > 1.0)) [ set speed ([speed] of (one-of turtles-at 2 0)) fd 1 ] [jump speed] ] ] tick end ;; increase speed of cars to accelerate ;; turtle procedure set speed (speed + (speed-up / 1000)) end ;; reduce speed of cars to decelerate ;; turtle procedure set speed (speed - (slow-down / 1000)) end to signal ifelse (any? turtles-at 1 0) [ if ([speed] of (one-of (turtles-at 1 0))) < (speed) [ set change? true ] ] [ set change? false ] end ;; undergoes search algorithms to change-lanes ;; turtle procedure show ycor ifelse (patience <= 0) [ ifelse (max-patience <= 1) [ set max-patience (random 10) + 1 ] [ set max-patience (max-patience - (random 5)) ] set patience max-patience ifelse (target-lane = 0) [ set target-lane 1 set lane 0 ] [ set target-lane 0 set lane 1 ] ] [ set patience (patience - 1) ] ifelse (target-lane = lane) [ ifelse (target-lane = 0) [ set target-lane 1 set change? false ] [ set target-lane 0 set change? false ] ] [ ifelse (target-lane = 1) [ ifelse (pycor = 2) [ set lane 1 set change? false ] [ ifelse (not any? turtles-at 0 1) [ set ycor (ycor + 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] [ ifelse (pycor = -2) [ set lane 0 set change? false ] [ ifelse (not any? turtles-at 0 -1) [ set ycor (ycor - 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] ] end I know its a bit messy because I am using code from other models from the library. I want to know how to create the collision of the cars. I can't think of any idea. As you notice my agent has almost the same size as the patch (I set it to 0.9 so that you can distinguish the space between 2 cars when they are set next to each other and I round the coordinates so that they are set to the centre of the patch). In my accelerate procedure I set my agent to turn left, move 1, turn right in a loop. I want to know if there's a command that lets me make the agent jump from one lane to the other (to the patch next to it on its left) without making it turn and move. And last, if you notice the code i created the car checks the patch that is next to it on the lane on its left and the patch in front of it and the back of it. So if the 3 patches on its left are empty then it can change lane. The fuzzy part is that when i run the setup and I press Go sometimes (not always) the car goes out of the 3 basic lanes. To understand this I have 7 lanes. The middle one which I don't use which is lane 0. Then there are 3 lanes on top of lane 0 and 3 below it. So the code I am using refers to the upper 3 lanes where I set the cars but for some reason some of the cars change lane and go to lane -3 then -2 and so forth. If someone can give me a tip I would really appreciate it. Thank you in advance. Tip: if you want to try this code in netlogo keep in mind that on interface tab I have 2 buttons one setup and one go as well as 3 sliders with names: number_of_cars , speed-up , slow-down.