In essence appellant's "greater public interest" exception is based on the proposition that property in public use may be expropriated where the best interest of the public will be served or the property put to a "superior and more important use". In support of this position, appellant cites Georgia Southern Fla. Ry. Co. v. State Road Dept., Fla.App., 176 So.2d 111; El Paso County v. City of El Paso, Tex. Civ. App. 357 S.W.2d 783; Mack v. Eldorado Water District, 56 Wn.2d 584, 354 P.2d 917; State ex rel. Puget Sound Baker River R. Co. v. Joiner, 182 Wn. 301, 47 P.2d 14; Snellen v. Brazoria County, Tex. Civ. App. 224 S.W.2d 305, and Houston S. Ry. Co. v. Kansas City, S. G. Ry. Co., 109 La. 581, 33 So. 609. In further support of this contention, appellant adduced the evidence herein previously mentioned. For present purposes, it suffices to repeat that appellant can furnish adequate, more dependable service at lower rates; that appellant pays taxes on its operations, that appellee can discontinue service at any time and that appellee has inadequate power facilities to meet the needs of its customers.

So plenary are the state's powers in eminent domain that it may take land for highway purposes even though the taking may trench upon the railroad right of way. State ex reh. Puget Sound Baker River Ry. Co. v. Joiner, 182 Wn. 301, 47 P.2d 14 (1935). Once the purpose for which the lands are taken has been adjudged to be public, the kind and type of roadway, the route to be followed, the design and engineering details become the subject of administrative decision.

[4] (c) A municipal corporation having the power of eminent domain has the right to determine what property is necessary for the public use to be made of it, and the action of its proper authorities in this respect is conclusive unless it is shown that such authorities were guilty of fraud or acted arbitrarily and capriciously to such an extent as to amount to a constructive fraud, or, as is sometimes said, there was bad faith, oppression, or abuse of power. State ex rel. Puget Sound Baker River R. Co. v. Joiner, 182 Wn. 301, 47 P.2d 14; State ex rel. Bremerton Bridge Co. v. Superior Court, 194 Wn. 7, 76 P.2d 990; State ex rel. Washington Water Power Co. v. Superior Court, 8 Wn.2d 122, 111 P.2d 577; State ex rel. St. Paul Tacoma Lbr.Co. v. Dawson, 25 Wn.2d 499, 171 P.2d 189; State ex rel. Northwestern Electric Co. v. Superior Court, 28 Wn.2d 476, 183 P.2d 802. Relators contend that the commissioners acted arbitrarily and capriciously to the extent that their action in selecting this tract should be set aside.

The necessity of taking land and public use decided by public administrative authorities empowered so to act, is binding on the courts in the absence of some showing of actual fraud on the part of such authorities or such arbitrary and capricious conduct as would amount to constructive fraud. Tacoma v. Titlow, 53 Wn. 217, 101 P. 827; Spokane v. Merriam, 80 Wn. 222, 141 P. 358; State ex rel. Puget Sound etc. R. Co. v. Joiner, 182 Wn. 301, 47 P.2d 14; State ex rel. Flick v. Superior Court, 144 Wn. 124, 257 P. 231; State ex rel. McPherson Brothers Co. v. Superior Court, 148 Wn. 203, 268 P. 603. Relators do not contend that the action of the state in this case constituted fraud in any manner. [6] The other error urged under this head is that there was no proof to the effect that the director of highways tried but was unable to agree with the owners for the purchase of the bridge, and that such neglect on the part of the state resulted in the courts having no authority to make the order of necessity.