Kiefer Sutherland's biggest challenge filming '24: Live Another Day' was London's traffic.
The 47-year-old actor reprises his role as CTU (Counter Terrorist Unit) agent Jack Bauer in the next installment of the action series, where he finds himself on the run in England's capital, and he admits he struggled to cope with the amount of road users in the city, insisting Los Angeles is "empty" by comparison.
He told the Daily Star newspaper: "Jack Bauer has been through some pretty dangerous and tricky situations in his time.
"But I don't think he has ever had to deal with anything as bad as London traffic.
"I mean seriously, I forgot how intense it is, it makes the roads in LA look empty."
Kiefer shares a "real connection" with London since he was born in the city before his family moved to California where he lived until him and his mother settled in Toronto where he was schooled.
He added: "I love London and England, though. I was born there and have a real connection with the country. So it is special for the new season to be set there."

Chantelle Houghton says Kelly Brook has "lost her mind" following her whirlwind engagement.
The TV personality insists the busty brunette is "gorgeous" and could do better for herself after David McIntosh - a former royal marine - popped the question last month.
Kelly and David have had an on/off relationship since they met on New Year's Eve (31.01.14) three months ago and although the former 'Gladiators' star spent a large amount of time at Kelly's north London home in the early stages of their romance, they reportedly split up shortly after Valentine's Day (14.02.14).
Chantelle told New magazine: "Has Kelly Brook lost her mind? She's gone from dumping him and erasing all traces of him from her Instagram account to saying he's the most wonderful man she has ever met.
"He's definitely not the most wonderful man I've ever me! Some people have said she's desperate to settle own and have kids, but she's gorgeous and could easily get someone better. I think she needs her head read!"
The happy couple announced the news on Instagram and posted a snap of them holding a balloon with the words 'Engaged' emblazoned across the front, but Chantelle was not impressed.
She added: "I hope the engagement balloon they were pictures with wasn't in place of an actual ring. Cringe!"

Miley Cyrus' beloved dog Floyd has died.
The 'Wrecking Ball' singer is completely devastated after one of her pet pooches, an Alaskan Klee Kai that she got in 2011, passed away yesterday (01.04.14) while she was on her 'Bangerz' world tour.
The heartbroken star posted on Twitter: "Today is the 2nd worst day of my life. I don't wanna say it because I don't want it to be real... But my precious baby Floyd has passed away. I am broken. I know I don't mean it but I wish he would've taken me with him this is unbearable. What am I gonna do without him? I am miserable."
Miley, 21, also apologised to her fans in advance if her performance is a little lacklustre at her Boston show tonight (02.04.14) after sharing two pictures of her cuddling up to the pup.
She added: "I'm sorry in advance if I am not myself tomorrow Boston. I will try my best to be my best."
The distraught Disney star's followers were sympathetic about her loss, and soon got "#RIPFloyd" trending on Twitter.
Miley - who owns several rescue dogs - is no stranger to coping with canine death after her Yorkshire terrier Lila was fatally attacked by her English bulldog Ziggy in December 2012.
The former 'Hannah Montana' singer even dedicated her performance at the 'VH1 Divas' concert to her departed mutt.
She wrote on Twitter at the time: "For everyone asking... I have never been so hurt in my life. My heart has never been so broken..... Lila my sweet baby girl has passed away."

Max George and Amy Willerton have fuelled rumours they are dating.
The Wanted singer and 21-year-old beauty queen were reportedly spotted locking lips in Brighton, South East England last month and Amy has now fuelled rumours that they are officially a couple by posting a picture of herself with the 25-year-old hunk and his mother Barbara on a lunch date on Mother's Day (30.03.14).
Amy posted the image on Twitter along with the message: "Champagne & oysters 🙂 babs you are so awesome! (sic)"
Max's mum seemed to be taken with the blonde beauty as she also took to Twitter to let her followers know how much of a good time she'd had with her son and his new beau.
She wrote: "What an amazing day we had!!! Xxx (sic)"
Amy then responded to Barbara saying: "Such a nice day!! We are officially hardcore going on that big ride 🙂 follow me sweetie so I can message you other pics! X (sic)"
The British model - who won the title of Miss Universe last year - followed up the conversation with her love interest's mum with a picture of herself with him and a friend on Instagram.
The caption of the photo read: "Who wins best pout queen? @therealmaxgeorge in the lead with eye popping dedication! (sic)"
Amy and Max are said to have been seen kissing at the Vodka Revolution bar following the 'Glad You Came' hitmakers' concert in Brighton.
A source said: "They were having a great time together and were kissing all night."

Russell Brand is releasing a series of children's books.
The British comedian is producing his own "interpretation" of classic fairytales, 'Russell Brand's Trickster Tales', which will be illustrated by Chris Riddell.
Russell previewed an extract from the first book, an adaptation of 'The Pied Piper of Hamelin' in a video announcement.
He read: "Once upon a time, long ago, in a time that seemed to those present, exactly like now, except their teeth weren't so clean and more things were wooden, there was a town called Hamelin..."
The 'Despicable Me 2' star went on to explain more about his literary project.
He added: "I know you've already heard of that. And you might think, 'Well, that isn't your story'. Yeah, I know, I've done a different version of it.
"It's the first of series called 'Russell Brand's Trickster Tales', where I do interpretations of fairy stories and folk tales, believing them to be the code to unlock aspects of our consciousness and to affect and impact the way we see the world.
"Once we start changing the way children see the world... we can do all sorts of stuff."
In the video, the 38-year-old star also showed off accompanying illustrations of rats.
Russell has previously released two autobiographies, a tome about his passion for soccer, 'Irons in the Fire', and is also working on a book about his views on ecology, rioting, and "the total mistrust of politicians".

Johnny Depp hates reality shows.
The 50-year-old actor is terrified of the modern world's obsession with material goods and reality star icons, and believes the shallow craze will be the downfall of society in a few years' time.
He mused to Interview magazine: "It's really frightening. And when you see all this stuff that goes on in the commercials - the endless commercials - people yelling down your gob, 'Buy this, do this, this will save you, this will fix you.'
"Everything can be a reality show now. Imagine what's it going to be in 20 f***ing years, man."
Johnny - who is engaged to Amber Heard and has children Lily-Rose, 14, and Jack, 11, with former partner Vanessa Paradis - also went on to apparently slam stars like the Kardashians and Paris Hilton by lamenting that talentless socialites have become idols to a whole generation thanks to the phenomenon that is reality TV.
The 'Rum Diary' star added: "People get famous now for I-don't-know-what. People have reality shows because they're a Hollywood socialite, and these things become very successful and they generate a s**tload of money for the company.
"And it's multiplying, to where you're literally looking into your next door neighbour's bathroom with reckless abandon. It is like watching a fire. You can't take your eyes off of it."

McBusted have confirmed plans to record a new album.
The supergroup - comprised of McFly's Harry Judd, Tom Fletcher, Danny Jones and Dougie Poynter, as well as Busted's Matt Willis and James Bourne - contemplated "laying something down" before their tour which kicks off on April 17 in Glasgow, but were unable to do so since members had personal commitments.
While they have all been busy with tour rehearsals, Tom and his wife Giovanna welcomed their first child Buzz into the world on March 13 and he has also been trying to spend some quality time with the little one, while Matt has joined 'EastEnders' as Stacey Branning's boyfriend Luke Riley.
Talking to London's Capital FM radio station, Harry said: "We were thinking of going in the studio and properly laying something down before the tour started.
"We've had no time because of Tom having his baby, the tour rehearsals and Matt's filming bits on 'EastEnders'. Everyone has been so busy."
The boys plan on working their new record following the tour which ends on June 2 in Dublin.
He added: "It will happen after the tour. We'll be writing on the road and hopefully soon after the tour we'll get in the studio."

'Coronation Street's Anna Windass will be wracked with guilt after sleeping with Pat Phelan.
The cafe worker - played by Debbie Rush - will struggle to cope after she deceives her boyfriend Owen Armstrong (Ian Puleston-Davies) by sleeping with the sleazy builder (Connor McIntyre) in a bid to save her family.
Debbie told SoapSquawk: "I don't think Anna will be able to cope with the guilt of sleeping with Phelan and I think it would be something that would really eat away at her."
Pat, who has CCTV footage of Anna's son Gary (Mikey North) beating him up and Owen locked in a building contract, bribes innocent Anna into sleeping with him in exchange of him releasing Owen and Gary from his control.
However, even though Anna is going through with something she's totally against in a bid to help her loved-ones, she could potentially destroy her relationship with Owen after he finds out she's gone behind his back.
Debbie explained: "Anna's trying to keep her family together and it does cross her mind that if she gives Phelan what he wants then he might leave them alone but to sleep with another man regardless of the reasons is a huge betrayal and I don't know if Owen would ever forgive Anna. She's trying to save her family but this has the potential to destroy them."

Mario Falcone doesn't "give a sh*t" about Lauren Pope.
The 'Only Way is Essex' hunk can't understand why his co-star, who he shared a drunken kiss with last year, is so upset that he took her friend Chloe Sims on a date.
He said: "I'm a bit confused by it, we [Lauren and he] shared a drunken kiss in Vegas and that's all it was.
'"Lauren was seeing someone at the time and I'm pretty sure - this is what I'm told - she got with Dan Osborne two days after me anyway, so we can't have been that serious.
"She making herself look silly ... I don't give a sh*t about Lauren - my only concerns are Charlie [Sims] and Chloe."
However, since Chloe and Mario's relationship was aired on the show last week, their romance has come to an end, which has left the busty brunette feeling "gutted".
She explained to Now! magazine: "I don't want it to be [over]. The only person we're concerned about is my brother Charlie, who's Mario's best friend. Once we knew he was alright I thought the pressure was off and we could carry on dating, but it's complicated.
"Today, I want us back together, but I'd only want that if he wanted it, too. I feel like I'm in love with him. I know he wants to settle down, but I don't know if he's quite ready.
"He's got a whole summer of fun planned with my brother in Ibiza and Vegas, so he can't commit when he's got all that going on."
Mario was previously engaged to his former co-star Lucy Mecklenburgh, but their relationship ended last year after he admitted he cheated on her with numerous girls.

Brad Pitt wants the Kings of Leon to play at his wedding.
The 50-year-old hunk is planning to tie the knot with Angelina Jolie, who he got engaged to in April 2012, and is hoping the band - which includes brothers Caleb, Jared, Nathan and cousin Matthew Followill - aren't on tour on the big day.
The 'Sex On Fire' rockers have a few UK dates lined up for the summer, including headlining Isle Of Wight festival in June, and Brad it hoping they can make "dates work".
A source told The Sun newspaper: "Brad ended up partying with Kings Of Leon last week. He spent most of the night talking to Caleb and he sounded them out about playing.
"It will happen if they can make the dates work."
Brad and Angelina - who met on the set of 'Mr. and Mrs. Smith' in 2005 and raise six kids together - have been trying to arrange the ceremony at their French chateau for the past three summers, but other commitments have delayed their nuptials.
A source added: "It's been a long time coming but finally it is going to happen."
Brad partied with Kings of Leon following the band's Los Angeles gig last week.
The 'World War Z' star arrived at at Warwick bar and restaurant with 'The Curious Case Of Benjamin Button' writer, Eric Roth, and made a beeline straight for the rockers at their official afterparty, before heading home at around 3am.

Kim Kardashian and Kanye West will spend £75,000 on each of their wedding guests.
The couple are expected to tie the knot in Paris next month in front of 200 of their loved ones, and last week those lucky enough to be asked to attend were given hand-delivered invites which each cost £600 to produce.
A source told Grazia magazine: "Kim and Kanye wanted the invites to be as lavish as possible and commissioned a couture designer to create gold silk boxes containing a photo album of their fairytale romance and a silk invite etched in real gold leaf with a clasp of natural pearls.
"It's the first glimpse their friends and family have had into their Paris wedding so they wanted them to be special."
The couple - who have nine-month-old daughter North together - are said to have hired the 199-room Trianon Palace Hotel for their guests, who will be flown by private jet to France, to stay in, and no expense will be spared for their comfort.
The source added: "Guests will be greeted with goodie bags containing £300 bottles of Bollinger champagne, £120 Creme de la Mer products, handmade souvenir trinkets with Kim and Kanye's initials etched in Swarovski crystals, bottles of scent from local perfumeries and £150 vouchers for treatments at the hotel spa.
"This is going to be the wedding to end all weddings and Kim wants to ensure that she and Kanye, as well as all their guests, have an experience they will never forget."
As for the bride herself, she is planning to don three wedding gowns on the big day, and is said to be having a spray tan containing real diamonds and 14-carat gold so that she "sparkles".

Katie Price will freeze her eggs if she gets too old to have more children.
The former glamour model - who already has four children, Harvey, 11, Junior, 8, and Princess Tiaamii, 6, from previous relationships and six-month-old son Jett with husband Kieran Hayler - isn't ready to add to her brood just yet but will take the precaution to ensure she can have more kids in the future.
Writing in her column for Now magazine, Katie, 35, revealed: "I would love to have another baby, possibly a few more, but I will do so when I'm ready. And I'm not ready yet. And if doctors say I can't have any more children, I'll freeze my eggs and then find a surrogate."
Although Katie maintains that getting pregnant again is the "last thing" on her mind at present, she recently admitted that she and her spouse Kieran don't use contraception, increasing her chances of an unplanned pregnancy.
She previously said: "I was amused to hear that a mag says I'm trying for a baby girl. Jett is only six months and I haven't got my body back yet! The last thing I need right now is another screaming baby. It's true I don't use contraception but I'm not planning to get pregnant and I'm not on a special baby diet."