Editor's note: A previous version of this article mistakenly said Tesla executive JB Straubel's KentPresents interview occurred this month. But the actual interview took place in August, 2015. The article has been adjusted to reflect the implications of the timing of this interview. The author regrets the error.

When asked about driverless cars during an interview at KentPresents last summer, Tesla Motors (NASDAQ: TSLA) chief technology officer JB Straubel said the electric-car maker was moving aggressively in this direction. Since then, Tesla has followed through with two major updates for its fleet that have enabled automatic steering, automatic lane changes, and the ability to summon Tesla vehicles in and out of garages. Ahead of the unveiling of its Model 3, some investors are wondering which autopilot features will be available for the lower-cost vehicle.

Tesla autopilot for Model S. Image source: Tesla Motors.

What's Tesla's next autopilot move?
Tesla's autopilot, or its driver-assistance technology, works great. But Tesla vehicles still have huge hurdles to overcome before they can drive themselves. Even Tesla CEO Elon Musk said in January that Tesla would need a next-generation suite of sensors with more redundancies to be able to build a vehicle that could drive itself. Notably, however, Musk predicted during the same question-and-answer session with press that Tesla will be able to build a car that can drive itself across the country, stoping to charge along the way, in just two to three years.

Musk's timeframe of two to three years is particularly interesting, as Tesla's lower-cost Model 3, which is set to be unveiled this month, is supposed to go into production late next year. Some investors, therefore, are likely wondering whether this hardware be built into Tesla's Model 3.

It's not clear yet whether the autopilot technology in Model 3 will rival Tesla's higher-cost models or not. With Model 3's $35,000 starting price at half the starting price of Model S and well below the $80,000 starting price of Model X, Tesla may be planning to use a more advanced autopilot hardware system in its more expensive Model S and Model X.

Currently, both Tesla's Model S and X come standard with safety-related autopilot features, such as blind spot warning and automatic emergency braking. Further, all Tesla vehicles include related hardware relevant to every available convenience-related autopilot features, which include automatic steering and lane changes on the highway. But customers must pay $2,500 to enable these convenience-related autopilot features, or $3,000 after delivery.

Autopilot upgrade for Model S. Image source: Tesla Motors.

What autopilot features will Model 3 include?
The question isn't whether Model 3 vehicles will be able to tap into Tesla's autopilot technology. Priced at $35,000, Model 3 will still be a premium car; the electric-car maker will almost certainly include at least some autopilot features. But the question is to what extent will autopilot be integrated? And what will come standard and what will cost extra money?

Investors may not get all their answers about Model 3's autopilot when Tesla announces it later this month. Tesla CEO Elon Musk said in February he hadn't yet decided how much information about the vehicle he would want to continue keep secret.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.