By John R. Quain, The New York Times Co.

On the des­o­late streets of Man­hat­tan dur­ing the bleak ear­ly days of the pan­dem­ic, Rose­mary Sigel­baum found that rid­ing a bicy­cle to work at Lenox Hill Hos­pi­tal offered a des­per­ate­ly need­ed respite from the stress of 12-hour days wit­ness­ing the worst of the coronavirus’s fright­en­ing effects.

“It was qui­et, and on my way home it gave me time to decom­press,” Sigel­baum said of her com­mute between the Upper East Side and her home on the Low­er East Side.

Those emp­ty avenues of late March have giv­en way to the city’s usu­al cacoph­o­ny of traf­fic, just as more peo­ple are dis­cov­er­ing the advan­tages of cycling to work: no crowd­ed sub­ways, bus­es or shared taxis. Bicy­cle com­pa­nies have post­ed out-of-stock notices for the first time in years. Sales in May sky­rock­et­ed 103% com­pared with a year ear­li­er, accord­ing to the NPD Group, a research firm.

But as all those new bik­ers are dis­cov­er­ing the joys of cycling, they’re also dis­cov­er­ing the dan­gers of rid­ing on two wheels, espe­cial­ly in cities.

Even before the pan­dem­ic, bicy­cle fatal­i­ties in New York near­ly tripled last year, to 29, from 10 in 2018. This year, at least 14 peo­ple on bicy­cles have been killed. With more bikes ply­ing the streets with cars, bus­es and trucks, there’s more pres­sure than ever to find ways to make the roads safer, for everyone.

The best safe­ty mea­sures are those that keep bicy­clists and motor vehi­cles apart, advo­cates say. Many cycling advo­cates are try­ing to cap­i­tal­ize on the pan­dem­ic pop­u­lar­i­ty of bicy­cles to push for more ded­i­cat­ed bike lanes.

It is “the pri­ma­ry method of address­ing bicy­cle safe­ty,” said Kyle Wagen­schutz at Peo­ple for Bikes, an advo­ca­cy group. Indeed, cities includ­ing Milan, Paris and New York have been adding miles of bike lanes this year, with more planned.

Still, bicy­cles and cars will have to get along, and safe­ty researchers are increas­ing­ly look­ing to tech­nol­o­gy for answers.

Last fall in Turin — before that area of Italy became a pan­dem­ic hot spot — a wob­bly cyclist skirt­ed a line of parked cars on a jammed sub­ur­ban street as a large sedan rapid­ly approached from behind. In the morn­ing driz­zle, the dri­ver was focused on a four-way stop that was com­ing up. Sud­den­ly, a warn­ing graph­ic flashed on a dis­play above the dash­board, indi­cat­ing that a bicy­clist was direct­ly ahead, and the dri­ver slowed to give the rid­er more room.

Such encoun­ters are part of a future vision of bicy­cle-to-vehi­cle com­mu­ni­ca­tions that could help pre­vent acci­dents. The Turin demon­stra­tion, sup­port­ed by Fiat Chrysler and the 5G Auto­mo­tive Asso­ci­a­tion trade group, involved a 5G wire­less pro­gram meant to illus­trate the advan­tages of high-speed com­mu­ni­ca­tions among cars, bicy­cles, traf­fic sys­tems and city infra­struc­ture. (This has an alpha­bet soup nick­name, C‑V2X, for “cel­lu­lar vehicle-to-everything.”)

The LINKS Foun­da­tion, a tech com­pa­ny, had out­fit­ted the demo bicy­cle with a glob­al nav­i­ga­tion device to deter­mine its pre­cise loca­tion and a 5G trans­ceiv­er to con­vey that infor­ma­tion to near­by vehi­cles. The con­cept envi­sions a future where every­thing — lit­er­al­ly the Inter­net of Things — is online to cre­ate smart roads and smart cities. Traf­fic lights will see cars com­ing, cars will see pedes­tri­ans at inter­sec­tions, and bicy­cles will talk to cars.

Some cyclists already use tech­nol­o­gy, like Garmin’s Varia radar tail­light, to warn of approach­ing cars, but it doesn’t active­ly pre­vent col­li­sions. Pedes­tri­an and bicy­cle warn­ing options for cars use advanced dri­ver assis­tance safe­ty sys­tems. Some, like Volvo’s col­li­sion warn­ing fea­ture, will even auto­mat­i­cal­ly brake for cyclists.

Such tech­nol­o­gy can reduce crash­es involv­ing cyclists and oth­er vul­ner­a­ble road users by up to 35%, said Russ Rad­er of the Insur­ance Insti­tute for High­way Safety.

That’s a tremen­dous improve­ment, but more can be done, because those warn­ing sys­tems rely on video cam­eras and radar in the car; they can­not see around cor­ners. Fur­ther­more, cam­era-based sys­tems rely on clas­si­fi­ca­tion pro­grams to pick out bicy­cles from what can be a clut­tered back­ground of mail­box­es, trees, garbage pails and tele­phone poles. A bicy­cle-to-vehi­cle sys­tem would send sig­nals around build­ings and hun­dreds of feet up and down roads.

“The prob­lem then is to com­pute the prob­a­bil­i­ty of the cyclist’s path,” said Daniele Bre­vi, a researcher from the LINKS Foun­da­tion in Turin who was run­ning the demon­stra­tion. Under­stand­ing the pos­si­ble tra­jec­to­ries of a bicy­cle and what crit­i­cal infor­ma­tion needs to be shared with near­by motorists is essen­tial to improv­ing safety.

“It can’t just be, ‘Hi, I’m a bike,’” said Jake Sigal, the chief exec­u­tive of Tome Soft­ware in Detroit and one of the found­ing mem­bers of the Bicy­cle-to-Vehi­cle Exec­u­tive Advi­so­ry Board. The group, which includes Ford, Gen­er­al Motors and Sub­aru as well as bicy­cle com­pa­nies like Giant, Spe­cial­ized and Trek, is work­ing to stan­dard­ize what safe­ty infor­ma­tion needs to be com­mu­ni­cat­ed in these so-called B2V transmissions.

It involves not only speed and direc­tion (is the cyclist going the wrong way in a bike lane?) but also infor­ma­tion such as a bicycle’s turn­ing radius and max­i­mum accel­er­a­tion and brak­ing — all data that would help pre­dict a cyclist’s path. E‑bikes, scoot­ers and sin­gle-speed bikes would have dif­fer­ent pro­files. Smart signs could also flash warn­ings when a cyclist was present to slow down drivers.

Sigal said the group planned to com­plete sev­er­al field tests of B2V sys­tems with Ford by the end of the year. Researchers will focus on reli­a­bil­i­ty and accu­ra­cy to ensure that the infor­ma­tion dri­vers receive is con­sis­tent and trust­wor­thy. Wire­less inter­fer­ence in urban areas and suf­fi­cient warn­ing times are oth­er crit­i­cal areas of study.

And while var­i­ous wire­less sys­tems could be used, the ini­tial tests are using Blue­tooth, a per­va­sive wire­less fea­ture that’s built into smartphones.

“We want it to be acces­si­ble to peo­ple who can’t nec­es­sar­i­ly afford a $200 bike com­put­er,” Sigal said. Android phones could be used, for exam­ple, by cyclists in con­junc­tion with inex­pen­sive sen­sors on bicycles.

In Turin, the issue of infor­ma­tion over­load also became appar­ent. An occa­sion­al bike warn­ing on a qui­et sub­ur­ban street seems rea­son­able enough, but a Man­hat­tan avenue could gen­er­ate an over­whelm­ing surge of warn­ings and alerts. So when to warn dri­vers may be just as crit­i­cal as what to warn them about.

While bike com­pa­nies are keen on find­ing active, high-tech solu­tions to improve bicy­cle safe­ty, they have also put con­sid­er­able effort into pas­sive safe­ty measures.

“Mak­ing the bikes more vis­i­ble to vehi­cles is crit­i­cal, and some of that is real­ly low tech,” said David Devine, glob­al prod­uct direc­tor at Can­non­dale. Inte­grat­ed day­time run­ning lights and reflec­tive side­wall tires are ele­ments that Can­non­dale has added over the years to improve safe­ty, he said.

Such tech­niques are about how cyclists can “cut through the visu­al noise of the envi­ron­ment,” said Eric Bjor­ling, brand direc­tor at Trek Bikes. The bike mak­er has worked with researchers at Clem­son Uni­ver­si­ty to improve the vis­i­bil­i­ty of its day­time run­ning lights and rec­om­mends rid­ers wear high-con­trast cloth­ing to stand out. The com­pa­ny is also work­ing on mak­ing hel­mets more affordable.

The crit­i­cal step is still to devel­op a stan­dard that bike mak­ers, automak­ers and city plan­ners can all use, Bjor­ling said. “And if cars in the future are going to be more autonomous, this is going to be need­ed to help AVs avoid rid­ers,” he said, refer­ring to autonomous vehicles.

Pro­tect­ing vul­ner­a­ble road users using net­worked com­mu­ni­ca­tions is inevitable, said Patrick Lit­tle, gen­er­al man­ag­er of Qualcomm’s auto­mo­tive busi­ness. “It will hap­pen over the next five-plus years.”

Mean­while, Sigel­baum has encoun­tered her own chal­lenges com­mut­ing on two wheels. She recent­ly broke sev­er­al bones in her hand falling off a bike, “all by myself.”

But she added, “I’m still going to bike to work from now on.”