The federal government’s top auto-safety regulator has conducted sharply fewer defect investigations in recent years, but newly released documents involving Tesla's Autopilot suggest the National Highway Traffic Safety Administration may be getting more aggressive.

The big picture: Federal authorities leave it up to automakers to assess the safety of their vehicles, pushing for recalls only when a defect is detected. But as automated driving systems make their way into more vehicles, consumer advocates say increased federal oversight may be needed to ensure public safety.

Driving the news: NHTSA has issued at least 5 subpoenas since April 2018 for information about Tesla vehicle crashes and its Autopilot system, Bloomberg reported, citing NHTSA correspondence with the electric-car manufacturer after a FOIA request by PlainSite.

• The exact intent of NHTSA's subpoenas is unclear.
• Auto safety consultant Frank Borris, a former top NHTSA investigator, told Bloomberg the use of subpoenas is atypical and could mean the agency “is gathering information that would be supportive of a formal investigation.”
• "If you do a subpoena, that's an investigation. Let's call it what it is," David Friedman, former acting administrator at NHTSA who's now at Consumer Reports, tells Axios.

Yes, but: NHTSA does not have an active defect probe into Tesla, nor will it necessarily launch one.

• In a statement, NHTSA said that it's “committed to rigorous and appropriate safety oversight of the industry" and encouraged any potential safety issue be reported. 
• Tesla defended the safety of its Model 3, citing NHTSA data and its own publicly reported safety statistics. In a statement, the company says they cooperate with NHTSA, but require subpoenas if consumer information is requested in order to protect their privacy.

Background: NHTSA stepped up its enforcement actions in 2015 in the wake of criticism that it missed clues about faulty ignition switches in GM cars that resulted in 124 deaths. Some other examples...

• It made Fiat Chrysler pay a $105 million civil penalty, hire an independent safety monitor, and buy back hundreds of thousands of vehicles as part of a sweeping settlement of safety-related issues in 2015.
• It also pushed for a recall of nearly 42 million vehicles from 19 different automakers to replace Takata airbags, in what NHTSA says is "the largest and most complex safety recall in U.S. history."

Enforcement has tailed off since 2016, however, beginning at the end of the Obama administration and continuing under President Trump.

• NHTSA launched 13 investigations in 2017, down from a record 204 in 1989, according to Consumer Reports.
• The agency told the publication the decline in investigations is due to a new era of improved communications with carmakers in the wake of several high profile safety scandals.

What they're saying: Friedman argues that private arm-twisting by government regulators is less effective because "you don't have much of a hammer."

• "Transparency, sunlight, the bully pulpit — that's what gets people to act," he says, citing recalled infant sleepers as an example.
• Jason Levine, executive director of the Center for Auto Safety, says he sees no sign that NHTSA is stepping up enforcement, adding that he feels regulators are too cozy with the industry.

Promising battery technologies are driving down the cost of electric vehicles to the point where they will be competitive with internal combustion engine cars by 2028, a top Energy Department official predicted.

The big picture: In response to tougher rules on greenhouse gas emissions, automakers are unleashing scores of new zero-emission, battery-electric models worldwide. But consumer demand remains low because they're pricey and charging access is an issue in some places.

What's happening: Costs are expected to fall soon, Michael Berube, the acting deputy assistant secretary for sustainable transportation, told a recent seminar, per Automotive News.

• Today's batteries cost $197 per kilowatt-hour to produce, which is why electric vehicles cost more than their gasoline counterparts.
• But technology advances are likely to bring the cost down to about $125 per kWh in the next few years, Berube said, putting EVs close to par with gasoline-powered cars.
• Plus, breakthroughs with lithium-metal and lithium-sulfur based batteries could drive costs below $80 per kWh by 2028, Berube predicted.

Yes, but: EV charging remains a potential threat to the technology's long-term success, he said.

What's needed: He said smart charging, which would allow EV owners to pull electricity off the grid at the most optimal time and store it for later use in vehicles, could be a way to buffer demand, per Automotive News.

Amid a decline in infrastructure spending, cities and local transportation agencies still pull together funding to address current and future transportation needs — but they could be taking on more ambitious updates, Henry Claypool writes for Axios Expert Voices.

Why it matters: Beyond repairing and improving roads and sidewalks, cities have an opportunity to build infrastructure that could open up alternative mobility options and increase accessibility for all.

The big picture: General infrastructure updates could have ancillary benefits for people with mobility concerns or who commute by bike, for example. These include...

• Energy efficient street lights to increase night visibility.
• Designated ride-hailing pick-up and drop-off zones to keep cars out of bike lanes and crosswalks — including ramps for wheelchair users and those with strollers and walkers.

But, but, but: Basic improvements wouldn't be enough to meaningfully expand accessibility — and municipal governments in many cases already struggle to make basic infrastructure repairs.

What's needed: Communities will also need to make investments specifically designed to improve accessibility like sidewalk ramps and audible signals.

The bottom line: With municipalities stepping up to plan for and invest in an autonomous, electric transportation future, there's an opportunity to implement infrastructure improvements that follow principles of inclusive, accessible design.

Go deeper: Read the full post.

Claypool is a policy expert affiliated with UCSF and AAPD, and a former director of the U.S. Health and Human Services Office on Disability.

ICYMI: The roots of Boeing’s 737 Max crisis: A regulator relaxes its oversight (Natalie Kitroeff, David Gelles and Jack Nicas — New York Times)

• Why it matters: The auto industry frequently holds up aviation as the model for safety but this important story is a warning of the risks associated with a hands-off regulatory agency letting companies assess the safety of their own technology.

Big loss: Uber’s no-good, terrible-rotten bad Q2 loses more than $5 billion (Jonathan M. Gitlin — Ars Technica)

• Why it matters: One-time IPO-related payouts to employees and drivers contributed to the giant loss, but "there's yet to be any real evidence that Uber's business model will ever do anything other than burn investors' money to make traffic worse." Uber's stock sank more than 12% on the news.

Electric unicorn: Bus maker Proterra may hit $1 billion valuation with new funding round (Alan Ohnsman — Forbes)

• Details: Proterra aims to raise $75 million in a private equity sale, bringing its cumulative funding to at least $600 million. The company said this week it's expanding beyond transit buses to sell its batteries, motors and other components to heavy-duty commercial fleet manufacturers.

This week I'm driving the Hyundai Elantra GT N Line, a sporty hatchback from the Korean automaker that is trying to up its game in performance vehicles.

The big picture: It's a replacement for the outgoing Elantra GT Sport, and goes head-to-head with the Honda Civic Si and Volkswagen Golf GTI.

Details: The GT N Line features a 201-hp, 1.6-liter turbocharged I4 engine and a sporty interior featuring leather heated and cooled seats with power lumbar support and extendable seat cushions. Red stitching and accents differentiate the N Line from the standard Elantra GT.

• A 6-speed manual transmission is standard, starting at a very affordable $23,300, and the optional 7-speed, dual-clutch automatic starts at $24,400.
• All the important safety features, however, come as part of a $3,850 tech package only available on the automatic version.
• It includes adaptive cruise control with stop-start capability, forward collision warning with automatic emergency braking, lane-keep assist, automatic high beams, and driver attention alert.

What to watch: The carmaker says it has more N Line models to come.