Concept of the Day: Audi A7 Sportback h-tron

November 20, 2014 § Leave a comment

audi a7 sportback htronAnd following Toyota and Honda, Audi’s showing a hydrogen-fuelled fuel cell car at the LA Show this week – but this one’s got a plug as well. The A7 Sportback h-tron concept is a plug-in hybrid hydrogen fuel cell, with an 8.8kW battery and a 50km/31-mile all-electric range in addition to the 500km/310miles it can do on a tank of H2; recharging takes two to four hours depending on power source. Electric motors – one up front, another at the rear – electronically drive each axle with no mechanical connection in the ‘e-quattro’ layout, giving 170kW, and it’s said to be capable of 0-62mph in 7.9 seconds. It uses around 1kg of hydrogen per 100km, said to be the energy equivalent of 3.7l/km of petrol (76.4mpg). This powertrain is ready for production “as soon as the market and infrastructure are ready”, said Dr Ulrich Hackenberg, Audi head of technical development. Full tech lowdown here. Sharing the tech, minus plug-in element, are the Volkswagen Golf SportWagen HyMotion and Passat HyMotion.

  • The Aachen University-based StreetScooter team has been turning out its lightweight modular-construction, purpose-designed EVs for clients including Deutsche Post DHL for a while now, but it’s now come up with a new short-distance, even lighter-weight model – and this one can be printed. All its exterior plastic parts can be produced by a 3D printer, using a Stratsys system, for build quality to match those conventionally-manufactured as well as speeded-up development – the StreetScooter C16 programme took just 12 months to produce a fully-functioning prototype. The 450kg C16 has an 80-mile range and can do 60mph; other upcoming models and variants on the theme include the Compact, a two/three-seater microcar, said to be currently in its prototype phase.
  • Mini’s doing the e-scooter thing – the Citysurfer concept, seen at the LA Auto Show this week, is an electrically-charged push-along which folds up and fits into the boot of a Mini hatch. It’ll do 15mph and has a range of 10-15 miles, more than enough for city-scooting on to a final destination. More here.
  • Citylab’s crunching some numbers to find out why Millennials are driving less – most likely due to their increasingly living a metropolitan life, they conclude. Debts, income, living arrangements (i.e. still with parents), later marriage/children etc. and other factors discussed, point made that if they end up following similar lifestyle patterns as older generations, just a bit later in life, their driving habits may not be different in the end – but if they don’t follow a traditional route to 2.2 kids in the suburbs, they could remain lower-mileage.
  • Some data from KPMG Automotive Network (via AutoblogGreen): though 57% of American households (115million of them) have two or more cars, this figure is dropping below 50% in some cities. Not just New York, but also auto-oriented cities like Los Angeles and Houston; this is down to operating costs in times of recession, and on-demand car-sharing services will see “proliferation” as an alternative to that second car, they say.
  • Rotary engine news: latest contender is the 70cc spark-ignition (diesel) X Mini, developing 5bhp at 15,000rpm. It’s intended for power tools and the like at the moment, but potential for scaling-up of the tech?
  • Software solutions provider Route Monkey is aiming to tap into integration of the transport and energy sectors and is expanding its EV-related team; current projects include working with Energy Saving Trust to map out the optimal locations for fast-chargers in London, reports EV Fleet World.
  • And of course, we can’t overlook the sewage-fuelled Bio-Bus, which is now up and running on the route (yes, the number 2) between Bath and Bristol Airport. Britain’s first poo-powered bus on public service, it’s running on biogas generated by Wessex Water from locally-produced human waste. More here

 

 

Honda FCV and fuel cell thoughts…

November 19, 2014 § Leave a comment

Honda-FCX-2016Honda has been leasing hydrogen-driven fuel cell cars since 2002 to selected customers, and has finally confirmed a date for formal launch and production of its FCV: March 2016 in Japan, with sales in the US and Europe to follow. Name to be announced nearer to the time. Latest version was unveiled in Tokyo this week – timed to coincide with Toyota’s launch of the Mirai – and Honda’s claiming a first in its powertrain layout: the entire drivetrain, including the fuel cell stack, is packaged under the bonnet, thus enabling a five-seat cabin (the Mirai’s only a four-seater). This also allows for the easier development of other bodystyles on the same platform at a later date. Developments from the earlier FCX Clarity prototypes include a downsizing of the fuel cell stack, 33% smaller but showing a performance improvement of around 60%, achieving a power output of over 100kW and power density of up to 3.1kW/L. The FCV has a single high-pressure tank for hydrogen storage, and Honda promises a cruising range of over 700km (434 miles), again outdoing the 300-mile Toyota; refuelling takes around three minutes.
Honda has further developed a couple of handy accessories and items of auxiliary equipment: also on display in Tokyo is its Power Exporter Concept, a device delivering 9kW of external AC power from the FCV, and its Smart Hydrogen Station, a mini-generator with a high-pressure electrolyser.

The week’s focus on fuel cells has got me thinking about hydrogen again; as a fuel, it demands energy for its synthesis and supply, and the establishment/expansion of an industrial infrastructure, just to produce electricity which can otherwise drive a car very effectively when supplied from an externally-charged battery. WTW carbon-impact lifecycle analyses bear this out. In the car, a fuel cell is still a complex and expensive thing to fit – again, to drive a motor which can be directly powered by electricity. But perhaps my biggest objection to hydrogen as a claimed fuel of the future is that it’s increasingly looking like a like-for-like solution for petrol/diesel on a business level and it lacks (though the advent of home electrolysers could change this) the disruptive potential of EVs, which can be charged at home or work, from solar/wind/hydro, without having to run to a filling station or engage with the oil companies.  Still, zero tailpipe emissions (apart from water vapour) can only be a Good Thing, and it does occur to me that, until the 400-mile EV arrives at a reasonable price, a fuel cell car is going to be easier to run for longer-distance drivers, especially those who (like me) have no access to domestic/workplace/somewhere to plug in overnight or for sufficient time to completely charge. That three-minute refuelling time is sounding pretty  convenient.

  • The Audi Prologue concept (upcoming A9) unveiled at the LA Auto Show this week features 48-volt mild hybrid tech. Energy recovery under braking of up to 12kW, mitigating the CO2 output of the twin-turbo V8 to 199g/km and fuel consumption to 32.8mpg, reports Autocar.
  • Well, it’s back… the Coda Automotive Sedan has been revived (yet again) as the Mullen 700e. Transport Evolved has a go at unravelling the long and undistinguished story of attempts to bring this rather sorry-looking ‘lectric saloon to market. It’s based on the mid-90s Mitsubishi Lancer, apparently (hardly cutting-edge even in its time) and was looking exceedingly dated even by the 2007 Los Angeles Auto Show, when it debuted as the Miles XS 200. Yeah, me neither.
  • Here’s a handy primer on power-to-gas – ‘free’ hydrogen using surplus renewable electricity (i.e. from turbines on a windy day, difficult to store) to electrolyse water. This can then be ‘stored’ in the natural gas grid in a process known as blending to decarbonise the gas supply system, as well as making use of otherwise lost energy; more here.

Monday news: Toyota Mirai, and more

November 17, 2014 § Leave a comment

toyota miraiToyota has named its fuel cell vehicle Mirai (“future”, in Japanese). To be launched tomorrow in advance of the Los Angeles Auto Show, the former FCV – a four-door saloon – has a 300-mile range on a tank of hydrogen and can be refuelled in less than five minutes, Toyota’s claimed advantages of hydrogen over electric vehicles. Text of company president Akio Toyoda’s speech here. Honda’s also showing its latest FCV, but production is now delayed till 2016.

  • BMW’s 2-Series Active Tourer is getting a plug-in hybrid option next year, reports Car magazine; a 102bhp motor is to drive the rear wheels in addition to the engine driving the front, making it 4WD.
  • The Atacama Solar Rally has started this week in Chile: 20 solar-fuelled teams are taking their very odd-looking vehicles 870 miles across the Atacama Desert; more here.
  • Wondered what happened to those Coda EVs? A handful of the saloons made by the now-defunct brand have ended up in Golden, Colorado, in what is thought to be the US’s first all-electric car-share. The eThos Electric Car Share scheme is offering short-trip on-demand rentals in the Golden and Denver metropolitan area, powered by locally-generated renewable electricity; more here.
  • The National Trust is trialling an all-electric Land Rover Defender prototype in Wales. Video here. It’s in operation on Snowdon, where the Trust is running hydroelectric electricity generation schemes as well as experiments with heat pumps, biomass and other technologies at its Hafod y Llan farm. More here.
  • The world’s biggest truck… is now electric, reports Green Car Congress. The20m-long, 800-ton GVW BelAZ 75710, in action at a mine in Kuzbass, Russia, features four Siemens traction motors each delivering around 1200kW; it can carry around 450 tonnes of cargo, around the weight of a fully-loaded Airbus A380. However, there’s a slight hitch in its green credentials: it’s powered by electricity from a pair of generators, each driven by a pair of 16-cylinder diesel engines.
  • Over 24,500 plug-in hybrids were sold in the Netherlands last year, where the tech has really taken off – but 80% of Dutch PHEV drivers spend less than half of their time driving in electric mode, according to a survey by Alphabet. Drivers are attracted by the tax breaks for PHEVs, the fleet management firm says, but not actually planning their vehicle-charging properly as they can fall back on their cars’ engines. It has now launched an eMobility app for drivers to better understand their vehicles’ capabilities and potential for fuel- and emissions-saving.
  • Growing algae by busy roads can absorb CO2, an experiment in Geneva found - as well as producing plenty of the green stuff for use in food supplements or even as biomass or in electricity generation. The algae was grown in tubes mounted to a bridge over a highway.
  • Some more details on the USAF trials of EVs and hybrids here, with some data on the V2G aspect – the 42-vehicle fleet’s capable of generating 700kW, enough to power 140 (large) American houses,

 

Design Concept of the Day: Ligier EZ-10 driverless shuttle

November 13, 2014 § Leave a comment

ligier ez10The Ligier Group has shown its driverless shuttle vehicle at the Michelin Challenge Bibendum in Chengdu, China, this week, and has partnered with Robosoft Technology to create the Easymile Company to market it.  Featuring video camera-based guidance tech (developed at the Institut Pascal) to position it on a roadway, the EZ-10 continuously monitors its path along a virtual track after an initial manually-driven journey down that route. It can detect obstacles – or people – in its path up to 50m away and stop or slow down automatically and can seat up to 10 (with four wheelchair-users). Designed for use on set routes at specific sites such as industrial complexes, airports and amusement parks (links between car-share and bike-share facilities are also mentioned), it can respond to multiple summons from call points or smartphones in an on-demand service. A fleet of five will now go on trial at the Michelin Europe Technology Centre, Ladoux. More here.

  • The Connected Car Expo takes place this week in LA; the keynote speech by “futurist” Peter Schwartz (wouldn’t mind his job title…) is previewed in a special Automotive News supplement. Schwartz talks about issues of consumer concern, security and regulation; the potential road safety, traffic and emissions benefits; and separating out the different roles of driving for essential transportation and driving for fun (the latter including personalised and selectable driving modes). Interesting quote about driving in 50 years’ time: “We will look back at driving the way people look back at horses today. Are there still people going out to ride horses? Yes, there are people going out to ride horses and they enjoy it, but we don’t use horses as transportation”. Does he mean driving as a pleasure/leisure activity for a wealthy, privileged few, then? (Probably yes, I reckon). BTW, some three-quarters of vehicles sold by 2035 will have autonomous capabilities, according to Navigant Research’s latest forecast.
  • Daimler’s Car2Go reckons it’s going to have 1million registered users by the end of the year, reports Automotive News Europe. Its ‘free-floating’ carshare fleet currently consists of 12,000 Smart Fortwos in 29 cities across North America and Europe, and it is about to expand into China, giving 60 locations by the end of 2016. Car2Go is yet to make a profit, however.
  • A 100m stretch of ‘solar road’ – said to be the world’s first – has been opened this week in Krommenie, the Netherlands. It’s only on a cycle path next to the N203 at the moment, but its PV panels sit under thick super-strength glass, and the electricity collected is thought to be enough to power streetlights and illuminate road signs. Ultimately, such roadways could power electric cars and nearby houses or buildings, claim the designers. A three-year trial is now underway; more here and at the SolaRoad website. This glass is expensive, though, and the system’s only 30% as efficient as simply putting PV panels on nearby buildings, says Treehugger.
  • All types of UK road traffic rose 2.2% in the quarter July-October 2014, to 77.9billion vehicle miles, the highest quarterly figure since 2008. Compared to the same period in 2013, car traffic rose 1.4%, light goods rose 6.9%, and totals are conclusively up compared to Q3 five years ago (up 1% compared to 2009); ten years ago (up 1.5% compared to 2004); and 18.8% compared to 1994. All types of roads saw higher traffic levels in the last quarter, with the greatest rise on urban minor roads (up 3.5%), and motorway traffic has reached a record high. So much for peak car?
  • A test fleet of V2X-enabled Hondas has taken to the road in Munich to start a 1300km tour across Germany, Austria and the Netherlands, communicating with traffic signals, smart traffic lights, congestion warnings and hazard alerts as they go. This is led by NXP Semiconductors in partnership with Siemens, Honda and Cohda Wireless, to showcase these countries’ ITS “corridor”. More here. (And details of Mexican research into data transference between vehicles here).
  • Australia: a 430km network of EV super-chargers – 12 locally-developed and manufactured Veefil points – is being built across SE Queensland, linking Brisbane with Noosa northwards up the Gold Coast and southwards to Byron Bay. More here. And also from the state: nanotechnology is the key to creating cars powered by their own supercapacitator-fitted body panels, say researchers at Queensland University of Technology. More here.
  • More here on the Fraunhofer Institutes’ development of the self-charging EVs: the Afkar project in Stuttgart involves an EV parking itself, finding a space with facilities for recharging (using wireless induction) and even moving itself on once charged to free the charger up for another car. This has particular relevance for car-sharing scenarios, they say.
  • The US Air Force is to replace its entire non-tactical fleet with plug-in vehicles, with a view to using them as back-up power in an energy crisis situation, reports EV Fleet World.

 

 

Concept of the Day: BMW Light and Charge

November 11, 2014 § Leave a comment

bmw light and chargeBMW has unveiled a dual-purpose streetlight-cum-EV charging point at the Eurocities 2014 conference in Munich this week. Two prototypes are now in operation at the BMW Welt centre in the city, and are integrated into the BMW i ChargeNow network, so users can pay by smartcard or phone app. It’s proposed as a way to “seamlessly integrate a smoothly-functioning charging station network into the urban landscape”. Featuring a modular LED system, the lighting is said to be energy-efficient and effective, with up to four LED modules which can be fitted for night-time lighting on main roads, or one or two for low-level illumination in residential areas. The next phase of the project in partnership with the city of Munich, from spring 2015, will see these “grafted straight onto the existing local authority street lighting infrastructure, substantially increasing the number of public charging stations at a stroke”. The charging points will be compatible with non-BMW EVs as well, and provider-independent via the Hubject e-roaming platform. More here.

  • Some predicted figures for European EV sales via Automotive News Europe: LMC Automotive expects 150,000-250,000 a year by 2020 in a total global market of 19.3million, with 53,000-odd this year (up from 31,615 in 2013). JATO Dynamics has counted 24,000 EVs sold in the first half of this year (over twice the 12,480 at the same point in 2013), with the European best-seller the Nissan Leaf, followed by the Tesla Model S and BMW i3. These three accounted for over 10,000 of the sales.
  • Here’s a new phrase to use in the context of connected cars: “swarm intelligence”. Daimler’s considering this with reference to automated driving technologies; an executive explains to ANE that this is part of a three-pronged vision involving the car as electrified, gradually automated, and as “part of the internet” – not just connected to it, but able to communicate with other vehicles, road users, infrastructure and so on.
  • A racing-developed chassis forms the basis of the North Carolina-made EV Fleet Condor pick-up, a nicely mean-looking truck just launched Stateside. It’s promised to be tough, fast – and affordable to buy and run. It does 80mph and 100 miles on a full charge. I rather like the thought of these running around working in the Blue Ridge Mountains…
  •  And Audi has launched a car-share platform called Unite in Stockholm: the idea is that five people (neighbours, family, work colleagues) choose a car to use on a pay-as-you-go basis. Monthly invoices can be split individually or shared between the co-drivers evenly, and include servicing, maintenance and Stockholm’s congestion charge; cleaning inside and out is an extra-cost option. Cars are reserved and monitored via smartphone app and ‘beacon’ transmitter (so you can see where your co-drivers in your ‘circle’ are going?). Interesting.

Transport Select Committee evidence

November 7, 2014 § Leave a comment

LEAF with Rapid Charge unitTranscript of the oral evidence given to the government Transport Select Committee ‘Motoring of the Future’ discussion, Monday 3rd November, has been published; evidence was given by Prof Phil Blythe (Newcastle University), Denis Naberezhnykh (Transport Research Laboratory), Graham Grant (Newcastle City Council), Andy Eastlake (MD, Low Carbon Vehicle Partnership) and Dr Colin Herron (MD, Zero Carbon Futures). Discussion included the roles and progress of OLEV and local authorities, the ‘piecemeal’ nature of governmental support, how infrastructure has been deployed in Newcastle/the north-east (relatively high EV population), different alt-fuels and their use in different types of vehicle, changes to VED and road usage-charging, the need for a strategy on grid capacity, V2X communication and open data. Some highlights and take-out quotes:

PB: “We are seeing a trend of adoption (of EVs and PHEVs), but not the sharp curve that was predicted initially. That follows virtually every other country in the world”. Recommends subsidies, incentives and “an appropriate charging network that is available to all”, citing Norwegian policy as an example of good practice; need to understand optimum locations for charging points.

DN: “There is still a lot of work to be done to understand what people actually want from these vehicles”; GG: “a lot of it is to do with perception. A lot of the dealers in our area provide seven-day trials of electric vehicles, because just taking them out is not enough. Generally, they say that when they manage to get people to take up a seven-day trial, they invariably buy them.” AE: “It is probably a longer game than perhaps was anticipated at the outset.”

DN: points to need for mix of fuels to 2050, fuel cell, hybrids, but “in reality, in order to hit the targets for the decarbonisation of transport, we are looking at electrification—in one way or another…  almost all vehicles in the future, as far as we can see, will have some form of electric drivetrain, which means that they will all be able to benefit from charging technologies and from developing battery and energy storage technologies. Electrification is the only way we currently know of that can meet the targets that we want for decarbonisation and air quality.” Research in London found existing charging infrastructure “completely unsuitable” for freight fleets, however.

PB: On benefits (safety, congestion) of autonomous vehicles and platooning; “connecting that to electric is logical, because they will be the next generation of vehicles; we should bring it all together. Then you can have intelligence on things like inductive charging”… DN: reiterates benefits of ITS for sustainability (GHG emissions, CO2, air quality) and transport system as a whole (congestion, traffic management); “we are seeing with electric vehicles, and vehicles that are electrified, is that they tend to be more intelligent anyway, because they need to rely on the infrastructure considerably more than traditional vehicles…  having an electric drivetrain of some sort makes it far easier to automate some functionality of the vehicle, whether it is steering, acceleration or deceleration. Those basic building blocks of autonomous vehicles are now easier to implement in electric vehicles.” Full transcript here.

  • And underlining why we need to work on this stuff, because cars aren’t about to dwindle in numbers on the UK’s roads any time soon (so much for ‘peak car’): 179,714 new ones were registered in October, marking the 32nd consecutive month of sales growth and 2,137,910 sold to-date this year, the first time sales have topped 2million since 2007. Good news in that is that ‘pure’ EV sales are 12,000 ahead of 2013’s total already, and sales of PHEVs and range=extended EVs are expected to quadruple by the end of the year, thanks to the new models coming on to the market. More from the SMMT.
  • Students at TU Eindhoven are building an electric motorcycle for the 80-Day Race. Team STORM Eindhoven says that electric motorcycles are an attractive way to improve the image of e-mobility and give potential to innovative in safety and smart energy management.
  • And another tilt at Tesla, seeking crowd-funding… Latvian/German start-up inabikari is appealing for investors to get involved with developing its Rev.01, said to be a Model X-type crossover promising a 400-mile range and 0-60 in five seconds, reports HybridCars. Its technologies will centre around clean energy generation and distribution, apparently, with innovations in areas including energy storage and capacitors.
  • The Dutch island of Tershelling is getting a 65-strong fleet of Nissan Leafs to share on-demand; these will be available to residents and visitors, and are expected to account for 10% of the 15-km long island’s motoring, reports EV Fleet World.

Design Concept of the Day 2: Peterbilt SymbiotUX

November 6, 2014 § Leave a comment

peterbilt symbiotiUXAnd this year’s entrants in the Los Angeles Auto Show Design Challenge: 2014’s contenders have looked at how the technology of 2029 will transform the relationship between humans and vehicles, including sensual connections and predictive behaviours, with specific reference to interior design. Pictured: Peterbilt Motors’ SymbiotUX, anticipating vehicles operating together in symbiosis, with the truck driver taking a role more like that of an aeroplane pilot; other entries are the Quros Qloud Qubed, which learns the drivers’ habits and preferences and kicks into autonomous mode if the driver starts to behave irresponsibly or out of character; the Honda CARpet with a flexible, shape-shifting carpet and a control-ball interface; the Infiniti SYNAPTIQ driver’s bodysuit; and a Honda-Acura biometric mesh interior fabric which can be pushed or pulled to configure the car’s interior and adapt to driver preferences. Rundown and picture gallery at Form Trends; winner will be announced on Nov 20th.

Plus some for-Friday reading: a round-up of extended essays and recently-found, relevant (to me, anyway) academic journal papers…

  • Big data, predictive analytics (again) and transport planning/deployment: in-depth essay at City of Sound looks at start-ups such as Bridj (on-demand buses directed to where there are clusters of users) and Urban Engines, which collects data on congestion (including crowds on public transport) to calculate and offer real-time incentives for people to delay or alter their journeys and modal choice; Dan Hill discusses the risk that the likes of Uber and other personal/private services might compromise or destabilise public transit, and the idea of predictive analytics providing the ‘bridge’ between private transport (i.e. motor car) and public (operating to fixed and inflexible schedules). And… more on autonomous cars vs. public transit (no, the former won’t displace the latter – it’s a case of the right solutions in the right place, and down to population densities) from Jarrett Walker at Human Transit.
  • A study in Spain, France, Germany, the UK, Poland and Italy, with 600 participants in each keeping an online travel diary, found that not only did most people’s daily driving patterns (including at the weekends) suit the range of an EV, their parking habits – the time their vehicles spent parked-up – were fine for typical recharging times, and that this information could be used for predictive management of electricity demand across the EU. It did note, however, that in all of the countries surveyed, few drivers had access to off-street or private parking, thus recommending on-street and public infrastructure in residential parking areas and garages.
  • Air travel bucks the trend for the reducing of greenhouse gas emissions as urban density rises; and in metropolitan areas there is a trade-off between car ownership and air travel among middle-income groups. Air travel, it seems, is counteracting any GHG gains made by reduction of car travel, according to this paper from Finland.
  • China’s rapid growth in car usage, fuelled by its expanding middle class and consumer society, may be slowing: ‘peak’ vehicle-mileage has now been observed in traffic-clogged Shanghai and Beijing, reports this paper. Demand for driving is high amongst young people and women in particular, as well as from active older people, but this is mitigated by an ageing society in general.
  • The vested interests of neoliberal governance structures mean than EU policies on sustainable transport will fail, claims this paper: Stefan Gossling and Scott Cohen cite specific “transport taboos” such as Germany’s no-speed-limits policy on the autobahn and describe market distortion and externalization and subsidising of costs, unwillingness of people to change behaviour, the small number of “highly mobile” people in upper-income brackets who account for a disproportionate amount of travel, lobbying by automotive and aviation organisations, social inequalities and emerging different societal structures as factors putting up barriers to change.
  • Looking at the mobility behaviour of Generation Y/millennials: Debbie Hopkins and Janet Stephenson suggest that researchers could use an “energy cultures” framework to analyse the norms, practices and material culture of this group, the external influences acting upon these three sets of phenomena, the interactions between them and thus how behaviours are shaped. As yet, not empirically applied, but a few ideas (one for theoretical discussions, with a few useful references).
  • And conversely, US baby-boomers (born 1946-64): over the last decade, they have become less car-dependent, but this is a trend confined to urban-dwellers, who are walking and using public transport more, and who also make more social, recreational and utilitarian trips than their suburban counterparts (at least in the Boston area, where this study was carried out). And a broad migration of older adults to urban areas is, the researchers conclude, unlikely, so measures need to be taken including making public transport and walking more attractive to suburbanites, who are making fewer trips, but still driving.
  • Life-changes are  interdependent and dynamically-interacting with residential and transport choices/behaviour, according to this Japanese study using life history research methodology. The researchers identified four key life-trajectory biographies describing mobility – residential (relocation), household structure (i.e. marriage, birth of a child, divorce, children leaving home), employment/education (including retirement) and car ownership (and other tools for travel, i.e. bicycles) and plotted cause-effect relationships between them. Car ownership was more sensitive to residential mobility than to household structure and education/employment.
Follow

Get every new post delivered to your Inbox.

Join 493 other followers

%d bloggers like this: