Gravity Model

[@zhenyupan9745]

Thank you for your video very much! I can understand the detail of the calculation process. It's very useful for me!

[@jermytomasoa6488]

I think the calculation for t13 are not correct (8:20)

[@apbosh1]

Thanks for the great explaination. Your t (1,3) workings are the same as t(1,2) in the presentation, I guess this was missed when you edited the video (unless i am missing something?) anyway the result is there and i just realised this was uploaded 10 years ago.

[@anjatschohl444]

Of glad someone noticed it too. Thanks

[@miltoncastor2176]

where did .89 come from?

[@alross4477]

hello is the last part Furness? also please explain k and for factors?

[@zaelaporrou]

Why travel time from a zone to itself changes? Isnt it 0?

[@mohamedelesawey5931]

Sometimes a small value of travel time is used instead of zero to account for internal trips within a zone. This will reduce the overall number of trips between each pair of zones but when it comes to traffic assignment, these trips will not be assigned to the network....

[@shashishankervlog]

If impedance of one zone is not given. In that case what value should I take?

[@fadykamal1953]

could any one please till me how to get the frictian factor

[@Montecristo_Jr.]

Πατήστε λάικ να νομίζουν οι ξένοι ότι είπα κάτι σημαντικό!!

[@Alebtong1]

That is the problem with these engineering videos they always assume that you know where they get there figures. I am yet to see a step by step video showing. How to collect model data , how you tabulate it and then how you start developing a model. Even my proffesor used these tables from a common text book by Beimborm Edward. Nobody ever gives a real worl example

[@mohamedelesawey5931]

The data is collected through a whole bunch of complex surveys. For transportation master plans, a Household Interview Survey (HIS) is usually undertaken for a sample of households in each zone. The samples are then enlarged to come up with the total production and attraction at each zone. For the impedence matrix, we can always start by the shortest distance between each pair of centroids. Or, alternatively, the free travel time matrix can be obtained by dividing the length by the free flow speed of each link. After the traffic assignment is done, you can calculate new travel time matrices. This is computionally very difficult if you do it by hands. Advanced software packages include tools to do that task. At the end, I know how frustrating that is when you learn it for the first time but in real-life it is so interesting and fun. Note that only a few people have such professional skills and background. I wish you the best of luck.....

[@USMANAKBARSunny]

another mistake is in explanation. when you says that production has to be equal to attraction. Which is infarct that the production should be equal to the target production and the attraction should be equal to the target attraction.

[@hadialsaadi3006]

how come the travel time from zone x to x have a value??? it should be zero man

[@olaabass8431]

can i know what source u use

[@hafedh12ify]

please help me out with trade matrix data base between countries ,1990-2012,export and import, i'm can't building my data base

[@monseigneur6365]

thank you

[@sudadalmutar4675]

I'm taking my FE exam this year and this topic is in our test material. not too easy not too hard, but needs some time to make the hand calculation plus a big concentration because those tables are so tricky!!...I'm assuming that they will not bring such a long question because you barely have 3:00 minutes for each question. and you needed almost 10 minutes to complete it with software assistance!

[@gabrielwaychison3227]

Thanks!

[@ndamchi1417]

i think the calculation for t13 is not correct