1^st Life Cycle Stage	Total Cost				Labor Cost
	Dependent Variable:		lntot		Dependent Variable:		lnlabor
	Indep Variable	Estimated Coefficient	Standard Error	t-Statistic	Indep Variable	Estimated Coefficient	Standard Error	t-Statistic
	one	4.73205	0.47258	10.01314	one	4.32551	0.42914	10.07945
	age	0.12385	4.50500e−002	2.74927	lyear	0.78063	0.15558	5.01760
	lyear	0.87737	0.17353	05.05593	elev	3.48566e−004	8.71128e−005	4.00132
	elev	3.91701e−004	9.00566e−005	4.34950
	Number of Observations		159		Number of Observations		159
	Corrected R-squared		0.30239		Corrected R-squared		0.20756
	Mean of Dependent Variable		7.21153		Mean of Dependent Variable		6.21859
2^nd Life Cycle Stage	Total Cost				Labor Cost
	Dependent Variable:		lntot		Dependent Variable:		lnlabor
	Indep Variable	Estimated Coefficient	Standard Error	t-Statistic	Indep Variable	Estimated Coefficient	Standard Error	t-Statistic
	one	5.57972	0.24429	22.84037	one	4.64925	0.20747	22.40961
	lyear	1.35616	0.10931	12.40674	lyear	0.91641	9.28310e−002	9.87185
	elev	2.27820e−004	4.75289e−005	4.79329	elev	2.46666e−004	4.03643e−005	6.11100
	aadt	3.03482e−003	7.75647e−004	3.91263	aadt	2.35182e−003	6.58724e−004	3.57026
	Number of Observations		448		Number of Observations		448
	Corrected R-squared		0.31453		Corrected R-squared		0.26197
	Mean of Dependent Variable		7.38172		Mean of Dependent Variable		6.35050
3^rd Life Cycle Stage	Total Cost				Labor Cost
	Dependent Variable:		lntot		Dependent Variable:		lnlabor
	Indep Variable	Estimated Coefficient	Standard Error	t-Statistic	Indep Variable	Estimated Coefficient	Standard Error	t-Statistic
	one	7.31532	0.25695	28.47024	one	6.31538	0.25468	24.79744
	age	0.11737	8.69821e−002	1.34939	age	0.19669	7.89160e−002	2.49238
	lyear	0.59437	0.32084	1.85257
	Number of Observations		94		Number of Observations		94
	Corrected R-squared		6.75674e−002		Corrected R-squared		5.30684e−002
	Mean of Dependent Variable		7.79547		Mean of Dependent Variable		6.86568