Note 8 – Property, Plant and Equipment

Our property, plant and equipment, net, consisted of the following (in thousands):

	September 30,			December 31,
	2017			2016
Machinery, equipment, vehicles and office furniture	$	3,671,297		$	2,154,367
Tooling		1,112,484			794,793
Leasehold improvements		716,015			505,295
Land and buildings		1,557,697			1,079,452
Computer equipment, hardware and software		360,533			275,655
Construction in progress		3,488,046			2,147,332
Other		23,886			23,548
		10,929,958			6,980,442
Less: Accumulated depreciation and amortization		(1,535,561	)		(997,485	)
Total	$	9,394,397		$	5,982,957

Construction in progress is primarily comprised of tooling and equipment related to the manufacturing of our vehicles and a portion of Gigafactory 1 construction. In addition, construction in progress also included certain build-to-suit lease costs incurred at our Buffalo manufacturing facility, referred to as Gigafactory 2. Completed assets are transferred to their respective asset classes, and depreciation begins when an asset is ready for its intended use. Interest on outstanding debt is capitalized during periods of significant capital asset construction and amortized over the useful lives of the related assets. During the three and nine months ended September 30, 2017, we capitalized $37.3 million and $96.0 million, respectively, of interest. During the three and nine months ended September 30, 2016, we capitalized $11.4 million and $30.4 million, respectively, of interest.

As of September 30, 2017 and December 31, 2016, the table above included $1.59 billion and $1.32 billion, respectively, of build-to-suit lease assets. As of September 30, 2017 and December 31, 2016, the corresponding financing liabilities of $17.5 million and $3.8 million, respectively, were recorded in accrued liabilities and $1.62 billion and $1.32 billion, respectively, were recorded in other long-term liabilities.

Depreciation and amortization expense during the three and nine months ended September 30, 2017 was $197.5 million and $534.2 million, respectively. Depreciation and amortization expense during the three and nine months ended September 30, 2016 was $126.8 million and $337.9 million. Gross property and equipment under capital leases as of September 30, 2017 and December 31, 2016 was $612.3 million and $112.6 million, respectively. Accumulated depreciation on property and equipment under capital leases as of these dates was $88.3 million and $40.2 million, respectively.

We had cumulatively capitalized costs of $2.85 billion and $1.04 billion, respectively, for Gigafactory 1 as of September 30, 2017 and December 31, 2016.