cameras on several east bay freeways that have seen dozens of shootings. that and the latest on the attack in france tonight at 6:00. >> that will do it for us. we'll see you at 6:00 after "nightly news." breaking news tonight. horror in france. massive panic as a truck slams into a crowd celebrating bastille day. tonight awful scenes of carnage. reports of many dead. and a major police operation is under way and fears it could be terrorism. wild veepstakes drama. more breaking news as donald trump picks a running mate. a roller coaster day hours from the big reveal. supreme sorry. under fire over comments slamming donald trump, a stunning walk-back from justice ruth bader ginsburg. road rage alarm. so common it's now involved in over half of fatal accidents. and law enforcement is concerned. and how accurate are all those fitness trackers millions wear everywhere they go?

our correspondent tried them and came up with some surprising results. "nightly news" begins right now. from nbc news world headquarters in new york, this is "nbc nightly news" with lester holt. good evening to our viewers in the west. we'll get to all the vp drama in a moment, but first there is breaking news from france. just horrific scenes right now out of the seaside city of nice after a truck slammed into a crowd celebrating bastille day. the french national day. french authorities say 75 people have been killed and some 50 more injured. and there are fears that this could be a work of terrorism. nbc's kelly cobiella has the latest. >> reporter: the moment captured on cell phone when a truck plows into a crowd. hundreds running for safety. witnesses panicking. >> we started hearing shrieks

and at the first moment people were running they were zig zagging left and right. we didn't know which way to run. i have never seen anything like it. people just leaving strollers, leaving bags on the floor and running at full speed in the opposite direction. the looks of complete terror and panic on their faces. >> reporter: it happened on the promenade in nice on the famed french riviera. one eyewitness said the truck hopped the curb, zig zagging at a high speed and reports of shots fired. the interior ministry saying several dozen are likely dead. the french president holding a crisis meeting. the mayor of nice warning people to stay indoors. fears of another terrorism attack. >> people taking a truck or a small car and ramming them into individuals or crowds in order to kill them with the most improvised device they have at hand. >> reporter: it comes eight

months after the isis attack on paris. several sites struck then. cafes, the soccer stadium, the theater. more than 120 killed. a state of emergency was declared and is still in effect today. late tonight french officials confirmed the truck driver did, in fact, fire on the crowd and had explosives and grenades in the truck. lester, he was killed by police. >> kelly in our london bureau. earlier tonight i spoke with american journalist bob franken who is on the ground in nice, france. i asked him what he was seeing when he joined us by telephone. >> reporter: at the moment, the promenade des anglais is very quiet and you see a few emergency vehicles moving up and down, but although a witness -- i did not see the truck itself. witnesses said that it jumped the pedestrian area, which is right along the mediterranean, and started mowing down people. i immediately went out there and i counted a dozen bodies both

dead and injured. and chaos. meanwhile, people had gone racing away by the thousands. this was bastille day. there was a fireworks display, as kelly said. it had just concluded when this incident occurred. the police were trying to get people to go down to the beach on the mediterranean. their concern was that there might be a follow-up of some sort. then a person said that the mayor is saying that people should stay home because their might be some sort of follow-up. >> and from what you saw and the pattern of victims in the street and what you're hearing, was there any doubt that this was an intentional act? >> well, no. no doubt whatsoever. neither the police nor witnesses said that this was anything but an intentional act, as you put it. the truck just mowed people down. there is some question about

whether there was, in fact, gunfire. as i said, the fireworks display was just ending, but the truck stopped a few hundred yards up the roadway. >> bob franken on the ground in nice, france. we can tell you in the wake of the attack there is breaking news that donald trump is postponing his vice presidential pick originally scheduled tomorrow morning. tonight sources tell nbc news that trump has chosen indiana governor mike pence as his running mate. nbc's katy tur has late details on that. >> reporter: it's governor mike pence, sources with direct knowledge say donald trump has found his running mate in the indiana governor. as late as this afternoon there were still three contenders in the race. former house speaker newt gingrich, new jersey governor chris christie and indiana

governor mike pence. ultimately what happened was that donald trump decided that he wanted somebody who could balance him out. and tonight you're seeing governor pence come off of a plane in new jersey on his way to donald trump's new jersey golf course where he will stay overnight. tomorrow we'll get the announcement at 11:00 a.m. governor pence impressed donald trump the other night when he opened for him in indiana. sources tell me that they were expecting him to be quiet. instead he was quite vocal and quite an attack dog. so why did he pick pence? donald trump said he wanted somebody with legislative experience. for many, that's pence, an evangelical christian with ties to the grassroots. the former congressman from rural indiana rose to one of the highest house gop leadership positions riding the tea party wave to indiana's governorship in 2013. >> here in indiana we've been proving every day that we can balance our budgets, run our schools, choose our health care. >> reporter: he was facing a tough reelection fight in indiana but will get back on the national stage where it could be rocky. at odds with trump on trade and his temporary muslim ban which pence calls offensive and

unconstitutional. a ticket that represents some of the divide between the gop and its presumptive nominee. real caveat here, trump is unpredictable and he could change his mind at any moment. we will not know for sure until the name comes out of his mouth. lester? >> thank you. for more on what it means to the truck campaign let's turn to chuck todd, moderator of "meet the press." chuck, did trump go with his heart with this pick or with political practicality? >> definitely not his heart. that's what makes the pick untrump like. it is a very normal political pick. a fairly safe, conventional pick. mid western governor, the midwest is an important part of the swing states. in a way this is donald trump accepting professional political advice. advisers are telling him you need a mid western governor to win iowa, ohio, michigan, pennsylvania. then getting a governor from

indiana will help you do that. that's what makes this a fairly risky pick if you're donald trump. you ran against conventional, against guys like mike pence. is this a way to keep the party together for the convention and a do no harm pick or does trump at the last minute go, you know what? i have to go with my gut. that got me this far. if that's where he goes maybe it's newt gingrich or chris christie. >> chuck todd, thank you very much. tonight supreme court justice ruth bader ginsburg is add missing public criticism of donald trump was a bad idea. she's been criticized from the right or left for steering out of her lane for making negative quips in interviews. it may be hard to put the controversy behind her. pete? >> reporter: a surprising end to an unprecedented back and forth

between a supreme court justice and the presidential candidate. in a written statement, justice ruth bader ginsburg called her recent remarked ill advised and says she regrets making them. judges should avoid commenting on a candidate for public office. and she promises to be more circumspect. in recent print interviews she called donald trump a faker with a big ego and joked that she might move to new zealand if he's elected. he responded by saying she should resign and she might be losing her mental fitness. tonight trump says that while justice ginsburg's statement is not an apology, she admits making a mistake and he accepts that. lester? >> pete williams at the supreme court, thank you. a severe weather alert for millions tonight as fast-moving storms like one here in new york today sweep across the northeast. and in the midwest powerful thunderstorms blew through the region. wichita, kansas, strong winds tipped over a semi truck on the highway. gusts up to 70 miles per hour also knocked down a number of trees and power lines.

now to more of our nbc news exclusive interview with syrian president bashar al assad. tonight we hear assad blasting the u.s.-led offensive against isis inside his country. and again, this interview was filmed by the syrian presidential press office, but there have been no editorial changes to the content. here's nbc's bill neely. >> reporter: tonight from syria's leader, harsh words for president obama, calling u.s. air strikes against isis ineffective. is that a military fault or is president obama simply not being, let's say, ruthless enough? >> it's not about being ruthless. it's about being serious. it's about having the will. the united states doesn't have the will to defeat the terrorists. >> reporter: but assad has faced global criticism for air strikes on civilian areas and

purposefully at times blocking food for tens of thousands including children. do you ever see pictures, photographs, videos of children, for example, in rebel-held areas? and i wonder if you have seen those photographs, what do you feel, sorrow, regret, nothing? >> my question, how could you verify that those children that you saw on the internet are in that area? >> reporter: you see, there you go again, mr. president. an answer like that simply reinforces people's views that you are evading responsibility, that actually you don't care for the people on the other side that your forces kill. >> that question could be answered if you answered that question, how can you blame now bush for the 1 million iraqi dead since the war in iraq in 2003? >> reporter: i'm not talking about president bush. i'm here to ask you -- >> i'm talking about the defenses now. >> reporter: and he says he's not worried about putin asking him to step down. he claims that's never been discussed. lester? >> bill neely in the mideast

tonight, thank you. still ahead this evening, driven to the edge. what a shocking number of people admit doing on the road that's linked to more than half of all fatal crashes. and which part of the country, experts say, has the worst drivers. also new sketches of the serial killer holding a city in fear. we're out with volunteers trying to keep the streets safe.

there is some troubling new research out tonight on something that many, if not

most, of us have experienced, aggressive driving and road rage. aaa reports it has become so common that a startling 56% of all fatal accidents involve at least one form of aggressive driving. here's nbc's tom costello with more. >> reporter: road rage in california. a limo driver takes a tire iron to the car behind him. in florida, an irate truck driver is so distracted giving someone the bird, he loses control and crashes. [ driver laughing ] >> that's what you get. >> reporter: also in florida, a couple on a motorcycle run over after exchanging words at an intersection. >> somebody just ran over somebody on a bike! >> reporter: the driver, robert vance, now charged with attempted murder. tonight aaa reports aggressive driving is now so common nearly 80% of those asked admitted they did it in the last year. tailgating, honking, rude gestures, cutting off, bumping or ramming other drivers. >> anger is a normal emotion. we all experience it. and that's okay. what matters is how we manage it. >> reporter: all too often not

so well says virginia state trooper anthony johnson. >> they'll go out in traffic and run people off the road and end up throwing like maybe a bottle or something. >> reporter: nationally 4 out of 25 road rage related fatalities in 2014, up 40% in four years. aaa says 19 to 39-year-old men are three times more likely to drive aggressively than women. and drivers in the congested northeast were more likely to honk, to yell or to offer an obscene gesture than drivers in the rest of the country. in oklahoma, 45-year-old eric caldwell is charged with assault with a deadly weapon after allegedly using his pickup to ram into two teenagers sending them careening off the road. the teens survived. caldwell's attorney isn't commenting and neither is robert vance facing attempted murder charges in florida. tom costello, nbc news, vienna, virginia. we're back in a moment with a tour de france pile-up caught on camera, but it's what came next that you really have to see.

an emotional scene in st. paul, minnesota, today as a driver killed by police during a traffic stop last week was laid to rest. a horse-drawn carriage led the funeral procession for philando castile. castile's death sparked nationwide protests when his fiancee streamed the aftermath live on social media. she claims he was reaching for his i.d. when an officer shot him. the incident is still under investigation. now to new developments in the hunt for a serial killer in arizona. the fbi joining the investigation as police release new sketches of the man believed to be linked to at least seven killings. many are on edge as darkness falls in a city where some are afraid to venture outside.

we get it all from miguel almaguer. >> we've got information about a serial killer in the area. >> reporter: tonight in phoenix, the guardian angels working what they are calling the killing zone. >> he comes out at night. you get out of your car, he shoots you. >> reporter: seven people have been murdered in cars or driveways here. police releasing this new sketch of the suspect today. >> he's going to kill again if he's not taken off the streets. got to get him off the streets. >> reporter: the extra security is welcome in this neighborhood. but it hasn't eased the fear that somebody else could be shot at any moment. police are looking into every tip. one lead ending in this high-speed pursuit in southern california. officers swarming a suspect. he matched the killer's description but was later cleared of any link. >> they are working day in and day out. i have faith and confidence in those detectives that that suspect will be found. >> reporter: sylvia and dosi ellis say their granddaughter, malia, just 12, was shot a dozen

times. their daughter stephanie, shot 14 times. >> these kids put their parents to rest, not the parents put their children to rest. >> reporter: tonight, families are grieving as the manhunt for a serial killer intensifies. miguel almaguer, nbc news, phoenix. a wild scene at the tour de france when a rider collided with a motor bike carrying a tv camera within today's final mile. it caused a pile-up that wrecked the bike of the overall leader, chris froome, but he took off on foot, shocking commentators who said they've never seen anything quite like this before. froome ran until he could get a replacement bike. the race jury let him keep his top spot citing unfair circumstances. there's more to come tonight. if you wear a fitness tracker, you'll want to hear this. we put several to the test to see if they are really accurate. results may surprise you. cova onhe part troratck frce.=

finally tonight a growing

number of people depend on them to count every step and every calorie. but just how accurate are those fitness trackers really? on "rossen reports," nbc's national investigative correspondent jeff rossen put several to the test and the results may surprise you. >> hands up. >> reporter: across the country the fitness tracker boom is on. >> one more! >> reporter: but how accurate are they? to find out, i'm wearing three fitness trackers on the same wrist. right here i have the jawbone up three. i have the garmin vivo smart hr and this is the fitbit charge hr. let's see what happens when i get to stepping. i walk around new york city for more than an hour. oh, baby. ending up in central park. >> everybody is talking about them. and everybody wants one. >> reporter: we're going to see which one is the most accurate. >> oh, my god, fabulous. >> reporter: just stop walking. time for the numbers. here we go. the fitbit says i walked 5,188 steps.

check the garmin. it says i walked 5,984 steps. so a lot more. but the jawbone says i walked the most. a whopping 6,271 steps. so what are you supposed to believe? >> hop up on to the treadmill. >> reporter: okay. to find out, i came here to the performance lab at new york's hospital for special surgery. that mask measures my calorie burn. my producers count 500 steps. >> 498, 500. hop off. >> reporter: well, that's comfortable. on steps, the fitbit was the closest with 502, the garmin 520 and the jawbone 559 steps. but the real headline here is the calories, right? we all want to know how many calories we burn. what is the official number from your computer? >> you burn about 19.9 calories, which is just about 20 calories in those few minutes of walking. >> reporter: this is amazing. none of them, i'm looking here, were even close. the jawbone was the closest saying 43.

that's more than double your number. >> yes. >> the next one. fitbit 67 calories, more than triple your number. the garmin came in the highest saying i burned 78 calories, nearly quadruple what i burned. >> not even close. >> reporter: the companies telling nbc news, the trackers are designed to motivate and encourage healthy lifestyles. garmin adding the position on the wrist matters. if multiple devices were worn at the same time and whether it's on your dominant hand. so this summer, go for a walk, go for a jog, but experts say don't expect absolute precision. jeff rossen, nbc news, new york. well, that is going to do it for us on this thursday night. i'm lester holt. for all of us at nbc news, thank you for watching, and good night. . ttreang

nbc bay area news begins with breaking news. >> that breaking news in southern france. dozens dead after a truck plows into a crowd of people, celebrating the country's independence day. thank you very much for joining us. >> it is now 3:00 in the morning in france. the country now on alert after an apparent terrorist attack. and we do have to warn you, some of the video we're about to show you is exceptionally disturbing. this is the latest video just in. watch that truck, you can see it speed up, and then it plows into that crowd of people.

witnesses claim the driver was also firing shots as he accelerated. this happening during a bastille day celebration in nice along the french riviera. >> reporter: a horrible late-night attack on hundreds of revelers who were celebrating bastille bay. french authorities giving us an updated figure. 77 people have been killed in that attack. many, many more injured. let's go to some of the video. you mentioned the white truck. that's how the attackers drove into the crowd gradually at first, then accelerating. then you see the people scattering. it happened as people celebrated on the streets. the prosecutor's office in paris we are told within the last hour has opened up a terrorism investigation. lots of videos from the scene are coming into the newsroom. they show hundreds of people running in fear moments after