The traffic is heavy this day, I arrive a bit late, so could you save me a place?A. can B. must C. need. D. might

What is the price of anarchy?Technically,in transportation engineering,the price of anarchy describes the difference between what happens when every driver selfishly picks the fastest route and what the socially optimal traffic outcome would be.In the pre-mobile-app days,drivers'selfishness was limited by their knowledge of the road network.In those conditions,both simulation and real-world experience showed that most people stuck to the freeways and arterial roads.Sure,there were always people who knew the crazy,back-road route but the bulk of people just stuck to the routes that transportation planners had designated as the preferred way to get from a to B But a new body of research at the University of California's Institute of Transportation Studies suggests that the reality is far more complicated.In some scenarios,traffic-beating apps might work for an individual,but make congestion worse overall.And autonomous vehicles,touted as an answer to traffic streets,could deepen the problem This problem has been vastly overlooked,"Alexandre Bayen,the director of UC Berkeley,'s Institute of Transportation Studies,told me.It is just the beginning of something that is gonna be much worse.The situation then gets much worse because hundreds of people just like you want to go on the side streets,which were never designed to handle the traffic,Bayen says."So,now,in addition to congesting the freeway,you've also congested the side streets and the intersections While it's clear that these apps can put stress on local side streets,we still don't know what effect they may have on highways,or for traffic systems as a whole.This is an open problem,said Bayen Hence,we need to be very cautious in our conclusions They re building on pioneering work by researchers like Hani Mahmassani into the role of real-time information in shaping traffic conditions.In 1991,Mahmassani challenged what he took to be"possible misconceptions that information will automatically lead to improvements in traffic conditions.He was not alone.That same year,other researchers noted that information can cause drivers to change their departure times in such a way as to exacerbate congestion Nonetheless,most of this early work showed that when the percentage of drivers with access to in formation was low there was a major benefit for better-informed drivers.So,in the early days of Waze and Google Maps and automated routing at UPS,many individuals did experience substantial benefits rom these applications.The roads,as a whole,were probably also flowing better.Bayen does,in fact,have a suggestion for improving these apps,but the companies might not like it.He thinks the apps should spread out drivers on different routes intentionally,which would require collaboration among the mapping apps.Given the cutthroat nature of competition in Silicon valley thats a tough sell but it might help bring down the price of anarchy
People can benefit from mapping apps when

A.there are more traffic apps available
B.only a minority of drivers use the apps
C.the roads are in better condition
D.the apps are more intelligent

I__________have been there,but I__________not find the time.

A.should；would
B.should；could
C.might；could
D.could；could