Condemnation proceeding under Chapter 136 to take a portion of defendants' property for highway improvement purposes; whether the trial court abused its discretion in excluding expert opinion testimony on valuation offered by defendants because the trial court did not consider admissibility of the testimony under Evidence Rule 702 rather than N.C.G.S. 93A-83; whether it was improper for the trial court to instruct the jury that the jury should not consider the taking and use of adjoining lands of others for the same undertaking in determining just compensation.